I just use Stremio + RD(Torrentio) on my TV, laptop and phone as they share the same public IPv4 address and I'm definitely not crossing the limit of 32 connections per server. I recommend that setup, gets rid of running a homeserver all time.

If you want to stick with your VPN and homeserver setup, get rid of Kodi and host Plex_debrid on your server, that way you can connect as many devices you want to Plex but only your server will be the one connecting with RD servers, letting you stay within the restrictions.

100Mbps symmetrical FTTH for $11/month. I get 120Mbps in real world scenarios(P2P, Good DDL servers) maybe due to Dual Stack Lite ISP?