Stubborn ABS traction ECU speed sensor issue C0200 C1235

I've been reading Prius chat forums over the past 10 years. I've looked up the codes and read 8 different posts so far. I am yet to find a solution. There may be an older post I haven't come across yet. It's not my intention to waste people's time, but I need to fix this issue before I go crazy.

I own a couple Prius's, gen 2 and gen 3. '07 has 137k miles and has been in upstate NY over the past 7 years. I am planning on replacing it and want to fix this issue asap. I think there was/is multiple layers to this issue. I may have fixed some of them. Initially it started with slip, brake exclamation, and ABS lights. They first came on about a year ago. It was winter. I took it to a mechanic I trust. He said there was C0200 C1235 C1236 codes and front wheel speed sensors were bad. He replaced them with after market sensors but the issue wasn't resolved. He said there could be multiple other issues (missing/rusted CV axles teeth, ABS ECU, etc.) for these codes. I didn't have time to look into it further and drove it for a year with ABS lights on. If the car sat for a few days the lights would go away. During the first ride you accelerated over 40 mph, slip, exclamation, and ABS lights would come on and throw C0200 C1235 codes. If you drove over 62mph, red 'BRAKE' light would also come on and odometer started reading zero until you came to a full stop. Then, ABS lights would stay on, but BRAKE light would go away and odometer worked fine as long as I cruised below 62mph. Because of road conditions here in upstate NY, it was time to work on the front end. I bought all the parts (struts, cv axles, discs-drums-pads-shoes, tie rod ends) I was going to need 3 weeks ago and started working. I replaced all 4 strut assemblies (all dead, clunking, bad ride) with Monroe's over a weekend. A couple days later, my wife got the triangle of death. I scanned the car with BlueDriver, got P3000 and P0AFA, took the traction battery cover out and tested all cells. It's the OEM traction battery. All cells read between 7.82 and 7.87 V. I read a few posts here and looked at the traction battery ECU. There were 3 pins, corroded and snapped. I replaced the ECU and harness with used OEM parts I got on eBay. The triangle and codes were gone after reset. I didn't rebuild the battery pack. I don't know how reliable the app is, but the battery pack passed full battery test and scored 61.7% on life expectancy test on Dr Prius app. I continued to replace both tie rod ends (had play), both discs (worn-out with grooves) and pads (metal scratching), both OEM drums (rusted bad) and shoes (half-worn but got them in the set, so...), and both CV axles (play and noise while cornering) with aftermarket parts (Monroe, Delphi, Powerstop, Cardone). I also replaced transaxle fluid with OEM Toyota WS because I lost couple quarts while swapping axles and it had over 30k miles on it. When I took out driver side axle, I realized thin metal dust caps (ones which go around axle abs teeth) were missing on both sides. I ordered and installed those with axles making sure the holes lined up with sensor holes. I also bought LAUNCH CRP123X OBD2 Scanner on Amazon to get data on sensors and transmission. I cleared codes and drove it to test, same scenario as above at 40 and 62 mph... I took it to a local Toyota dealer for front end alignment and asked them to look into ABS issue. They said they drove it and were pretty sure it was either ABS ECU and/or TCM and quoted me $3,900 for a replacement ABS ECU. Dude, the car is worth around $4,500, lol... I bought a used OEM ABS ECU on eBay, took 1/4 of dash apart, used 3 sections of socket extensions (totaling 20 in or so) to take the last son-of-gun 10 mm nut off, replaced ECU, reset and test-drove it. Now, the orange slip indicator light doesn't come on, but orange exclamation and ABS lights come on if I accelerate over 55 mph (not 40 as above) and red 'BRAKE' light pops if I accelerate over 75 mph (not 62 as above) and odometer stops working. After a full stop, BRAKE light goes away, but explanation and ABS lights stay on and odometer works fine as long as I cruise below 75 mph. If I graphed the front wheel speed sensor compared to vehicle speed (transmission speed sensor, i think) on the scanner I had an erratic signal from the front right speed sensor. Yesterday, I replaced the front right speed sensor with an aftermarket sensor from eBay, but the signal is still erratic (see pic below) and I have the same orange exclamation and ABS lights (no slip light). Last night, I also realized the aux. battery was around 11.8V. I trickle-charged it overnight and tested with a digital battery tester I got on Amazon 3 years ago. It said it needs to be replaced: 13.51 V, SOC: 98%, SOH: 79%, R: 7.6 miliohm, 327CCA. It's stamped 04/19. I am going to take the Prius to Autozone, get it scanned and replace the aux battery tonight if needed.

I tried to keep it as brief as possible with details I remembered and don't mean to waste anyone's time. If a senior group admin or Toyota tech has any insights to this issue I would really appreciate their input. Is the TCM also bad? Can the used OEM ABS ECU or new aftermarket speed sensor I got be bad? Also if anyone has any troubleshooting guidelines for this issue from a Toyota repair manual I would love to see it. Wish everyone with stubborn electrical issues like this the best of luck, take care...