Now this is interesting. All this time i've been using flags and options and thought 'lemme try all defaults and test some things'
my mount right now looks like this
ExecStart=/usr/bin/rclone mount drive: /mnt/drive --allow-other --log-level INFO --log-file /opt/rclone/logs/rclone.log --timeout 1h --umask 002 --user-agent rclone --rc
i've never had better results and such fast playing/seeking videos on plex.