Short answer is the effect should be even overall, but what matters happens at state and district levels, so you could even disenfranchise more people of your own party on the net and still end up with an improved electoral outcome.

You could steal the vote from 500k Republicans in just Alabama and 150k Democrats spread across Wisconsin, Michigan, and Pennsylvania and have a net swing of 0 EC votes lost and 50 EC votes gained for Republicans.

You just have to create policies (like closing polling place, making vote by mail difficult, create voter id rules that exclude college students) that have small partisan differentials in a few swing states, which is why the greatest effort and impact is in urban centers in the midwest (followed by Latinx populations in the southwest like AZ and NM, and African American populations in the southeast like FL and GA).

Most large urban areas are Democratic. In the time of COVID, would you rather vote by mail or wait in line at overcrowded voting locations?

Dems are more likely to be affected by polling station closures and consolidation, so that e.g. all of Detroit has to vote in a single location.

They are not. Republican leadership is convinced they are but consider this quote from https://thehill.com/homenews/campaign/510040-gop-fears-trump... :

> The R Street Institute, a think tank dedicated to free markets and limited government, recently released a study titled “Why conservatives should embrace sensible measures to expand absentee balloting.”

> The study cast doubt on claims that Democrats benefit from expanded mail-in voting, pointing to three states Trump carried in 2016 — Utah, Arizona and Montana — where about 70 percent of voters cast ballots through the mail.

GOP leadership is just totally unhinged.