Simple. The punishment for democrats rigging the 2020 election but not being proven until after the fact should be the ineligibility to run a candidate in the election following when the proof was given.
So even though they rigged 2020 and got their guy in, if it can be proven in 2025 that they did, in fact, rig the election, then the punishment should be ineligibility for any democrat to run a candidate for president in 2028.
It’s worth looking into for congressional elections as well. The same rule should apply there. Cheated in 2020? Found out in 2025? Congratulations, you can’t run a candidate in 2026 or 2028.
I would go beyond that. COMPLETELY OUTLAW THE DEMOCRAT PARTY.