Hello Nicolas, I know almost nothing about RAID (never used of set up one).
*Perhaps* you can toy with the --maxrecoveryrate Rate[bBsSkKmMgG] parameter of lvchange?
https://docs.redhat.com/fr/documentation/red_hat_enterprise_linux/9/html/configuring_and_managing_logical_volumes/troubleshooting-lvm-raid_troubleshooting-lvm https://manpages.debian.org/trixie/lvm2/lvchange.8.en.html
