My use-case is probably a bit different from most people here, but why not share my preferred roadmap focus:
1: Control Panel migration/replication/failover
2: NodeJS/python/etc options besides PHP
3: Safe auto-declutter + defaults (unused docker 'trash' cleanup, apt cache, logs/journald etc)
4: IPV6 (and ipv6-only for eligible roles) and inter-server private network communication
5: Migrating all settings with the website when moving it to another server (vhost, rewrite rules, php extensions, redis, fastcgi)