1987 LT80 Electircal Issue

I have an LT80 that ran great. The battery died, so I jumped it using a battery charger with to many amps. Now it will not turn over and the starter rely just clicks. If I bypass the starter relay the starter turns over (had plug out), but it took 20 amps to get it to turn over.

1) I am trying to determine if the starter relay is actually bad or is it the starter?

2) I read that I can buy a starter relay from AutoZone for 10 bucks, but there was no info on specifics. Any guidance?

3) Know where else I might get a starter relay switch?

Thanks!