That's some of the story. Some of it was bad candidates and well-funded independents.
Independents and Moderates who preferred Trump because they hated Biden/Kamala/Walz in 2024 may have chosen Dem. candidates or Independent candidates to a larger degree this go-round or simply stayed home out of apathy. All 3 of these decisions would result in net loss for Republican candidates.
Prime example of Independent impact is Tennessee: Bill Hagerty won his Senate vote with a comfortable 55% vs. 42% over the left's candidate. Marsha Blackburn won the Governor's race with only 45.5% of the vote, and her democrat opponent had 43%. The catch is that a VERY well-funded Independent ran directly against Blackburn and netted 10% of the vote. Again, these votes for Independents are generally going to take from the Republican candidates.
But make no mistake, some of it was simply bad candidates. For example, Brandon Gill won his district with a comfortable 55% total. And yet that same district chose Talarico over Paxton, and there was negligible influence on the Senate race from independent candidates. This means they HATED Paxton.
Georgia ran uninspiring candidates for Governor and Senator on the Republican side, as well.
Many were no doubt unimpressed with the lack of focus on voter priorities from 2024 by the G.O.P. and stayed home. So, like usual (1994 and 2010 come to mind), the votes swung the other way in the midterms. Helping make the impact larger, though, were independent candidates and lousy candidates by Republicans.