I’ll preface this with I don’t know much about these things so please explain to me like I’m 5!

I work from home full time and I can have about 40 devices on the internet if everything is on at once. 6 TVs, 5 phones, 8 computers, 4 tablets, 4 gaming systems, 2 outside cameras, 2 thermostats, 1 smart hub, 1 Alexa, 1 printer, 1 CPAP, and a bird feeder. So everything wouldn’t be on at the same time

I have 1 gig fiber internet (the highest available in the area and it says it only supports 15-20 devices) and a TP links Archer AX72 Pro AX5400 router.

Some family members say they have issues with the internet but I only ever notice it on the far side of the house (opposite side of where the router is). House is a tri-level split and about 2700 sq feet and the router comes in through the garage on the main floor, with bedrooms above it.

Mainly using for streaming but we have two kids who like to play computer games. I work 40 hours a week and a family member would like to WFH part time.

What are my options? Do I get a one mesh repeater? A range extender or access point? Are those the same thing? Do I need another source of internet? The area we see issues with are up stairs and across the kitchen into the dining room, so if we wire it, it would be across pathways and walls…