Back to the original question, instead of discussing what fluid is good.
Based on my experience owning Toyota, you just need to try to change the Trans fluid first.
It is not that difficult to do a trans oil cooler lines drain in the older Toyota, if you have the tools and can follow instructions.
There are a lot of Youtube video on it, all Toyota transmission have similar setup till they go to the sealed transmission.
So, you can check any Camry transmission fluid replacement which probably have the most videos.
For older Toyota, I have used Supertech ATF to Maxlife ATF and all of them works fine.
Don't overthink it.
Toyota trans is not picky.
Now, the transmission CAN fail also with age.
Actually, low mileage car is more prone to bad transmission since there is almost no fluid flow to lubricate it.
The seals goes bad faster in a vehicle that is not driven.
The solution is to actually drive it as much as you can.
Hopefully, everything is still good.
