All, he will have, at best, is a few accounts of individual bad actors in each state that tried some funny business with some votes, and maybe a handful of "human error" things that happened with the counts. The thing with these is:
1. You will find examples of this helping both Biden AND Trump. (but of course Trumps people won't be talking about the ones that benefitted him, but surely Biden's lawyers could dig up plenty, just like Donald's did.
2. The percentage of these bad votes to actual legit votes will be ridiculously small, so if you spent an insane amount of time, money, manpower, to ID them and threw them all out, they would still make no meaningful impact in the election.
and most importantly
3. These are all isolated incidents and would not be contributable towards or prove any sort of wide ranging, systemic, countrywide conspiracy to sway the election and cause mass piles of the vote (ie the mail in vote as a whole) to be discarded, and the decisions handed over to the courts or the legislature (ultimately Donald's hope here, but will never happen)
Remember, the election is conducted by the individual states who generally allow each individual county within to run their own show in counting votes. This existence of literally hundreds of entities doing their own counts purposely avoids any sort of large scale fraud that could happen.