I haven’t gone through all their work, but some of the delisted maintainers were working on driver support for Baikal, a Russia based electronics company. Their work includes semiconductors, ARM processors. Given the sanctions against Russia, especially for dual use stuff like domestic semiconductors, I would expect that Linus and other maintainers were told or concluded that by signing off and merging their code they’d be personally violating sanctions.
Simply become older. The older I get the less I want to do hours long sessions. But practically, I have a hard bedtime alarm on my phone, which works cause sleep deprivation and work suck.