Best hardware to reduce ping

Hi all im in need of some advice.

Im looking for any tips or tricks to reduce ping. I believe this is mostly out of my controls but just looking to see if theres anything ive missed.

For context: i game occasionally and the lag has been unplayable recently. Mainly this is down to my ISP being a 5g SIM card in a 5g sim router from Three Uk. I get great speed (between 500mb and 1.3gbps) because i live around 4 streets from the main mast.

I have the 5g router in bridge / modem mode feeding the internet into my TP Link Deco X50 POE mesh routers, i have 2 of these and they are both POE hardwired. I also have 2 unmanaged switches helping power all my ethernet runs and i only game on ethernet.

Once my package runs out i will switch to FTTP full fibre broadband to sort it out once and for all but i do wonder…

Is there anything else i can do? What if i switched from my deco mesh system to managed switches and access points, would it make any difference at all?

Ive seen other people mention about using openwrt on a router or pfsense to use there QOS and other features to help ping and prioritise gaming devices etc but i dont think this would make a difference for me given my deco mesh system has QOS already setup and prioritising my game PC right now…

Any advice?