Router-Mesh recomendations for environment?

In process of putting together system I can edit on and be stable platform to build on, based on running across your site and the knowledge you have, I purchased Synology -DS720- 2 Seagate Ironwolf 8TB drives with the additional sinology 4 gb ram- have not added the SSD yet? Still researching Desktop??, Adobe pro or Davinci resolve ??, considering ViewSonic VP3881 do to one monitor for multi-tasking and accurate color with a good price, not a gamer but who knows maybe experiment at some point.
I have a 2000 sq ft house 3 car garage trying to cover approx. 2500 square ft , would like to use POE injector WT-GPOE-8-Awhich I own for some cameras eventually currently not using, I have cad 5 & 6 ran to the 3 rooms MB, Living, Den from office router, currently have Frontier Fios only getting 60 up and down paying for 75 thinking to upgrade min 100 probably more gigabit if they offer special, would like system to be able to take advantage. Frontier wanted to send me there router to test the lines as they don’t support outside components, Frontier recommended I also purchase a mesh to get full coverage for all devices not wired direct you know how it is adds up in a hurry 3 Alexa’s, Garage Door opener, Heat & Air thermostat, Harmony wireless hub, TV added bedroom with no cad 6 ran,2- laptops, mobil phones it turns into another 15 devices real quick. I also own TP-Link 24-_port gigabit switch TL-SG1024 I’m not using but could maybe use in plan
Was thinking while upgrading get a fast compatible router that will work with Fios and also be able to support the Nas with a fast connection if accessing form outside, I have also watched some of your links on editing direct from the sinology at blazing speeds not sure on the configuration for that, but this would be nice to have option, plan was to build desktop with SSD and backup within? Use the Nas to carry the load of all the back up files and space for the cameras. Now with this statement from Frontier get new router for speed and get mesh for additional Wi-Fi coverage and speed what would you recommend?
Wish you were in Dallas I would be happy to pay for the design and implementation of something that all works together with new technology and stability.
Sorry for the lengthy explanation trying to give you clear picture.

Would be happy to purchase through your links.

The best WiFi mesh system is made by Netgear (Orbi) and AmpliFi (Alien). If you have a significant outdoor space to cover then Netgear can be handy with their outdoor mesh points. Otherwise Alien units, when located strategically, will reach even through the brick walls to cover surrounding outdoor space.If you have kids then Netgear and their Circle software will be a great help to limit what kids can or can not do and at what times. Otherwise, Alien mesh will simply care about maximum wireless speeds you could get. Bot system also allows connecting via LAN through their mesh systems.Regards to a NAS, SSD cache would help with things like Virtual machines, web server and multi-user environments where the same data is accessed frequently. If you want to do some direct editing from a NAS then a 10GbE based model would do a better job. But pioneers have tested and Qnap 5GbE USB adapter seems to work on a Synology. This would increase bandwidth speeds significantly.I hope this helps.