Installed smoothly here by OTA, too – miraculously not only preserving MindTheGapps, but also Magisk!
I remembered @marmistrz's instructions from April, kicked off the installation, and when it asked for a reboot, I opened the Magisk app to have it "install to inactive slot" before I would reboot – just to find no such option. A quick internet search led me to a notice by topjohnwu that said "Install to Inactive Slot is disabled in newer builds of the Magisk app due to changes that Google introduced to the OTA process", which dated back to 2020 and also detailed a modified upgrade method