Depending on how accurate you want to be, just use an App like "RPM Speed and Wow".
I have a 360° Disc that i used in the past. I just put it on the record, push the LP to the Pin in the 0° Position and make a measurement. Then you do 90° Steps and do the newton iteration from there (always take the half angle of what you measured best before).
This will give you the best general degree for the record, but ofc this can still mean you're out of center, but as a start thats easy.
ofc you can also go crazy and use something like a DS Audio ES-001 Eccentricity detection stabilizer.