Absolutely correct but from the context of the OP’s post it seemed they were trying to get more bandwidth for when multiple clients need it at the same time. Exactly what LAG connections can help you with. Of course it is much better to just use higher speed links but LAG connections certainly still have their place when you just can’t simply upgrade the connection speed at a reasonable cost.
Ring like topology is anathema to Ethernet networking. If you really somehow create a ring in your network it will cause problems. Most commonly your switches will detect a ring through spanning tree protocol (STP) and shut a link in the ring down. You always want to have a star topology in Ethernet networks. If you want more bandwidth or redundancy in critical links, use LAG connections.
Unfortunately this is typical for consumer router/wifi access point combos. They need to be restarted regularly. Mostly because they are underpowered for what they are supposed to do. If you want to get around that you need slightly more beefy hardware like a firewalla gold (highly recommended if you don’t want to tinker too much), a pfsense firewall device, ubiquiti edgerouter, TP-Link ER605, and many others. These do NOT integrate a wifi access point which in fact is the sign of a good router but you will need separate access points because of it. In many cases if you use one of these as a router, you can just switch your old router to access point mode and it will operate very stably suddenly.
I use a firewalla gold at home and it is rock solid. I use this instead of one of the others I mentioned because my spouse can control essential functions (shutting off internet for the kids when needed for example) from her phone which is not trivial on any of the other solutions and she doesn’t complain it is too hard to use. It has uptime measured in years instead of weeks.
Is your fiber on pppoe or IPOE? If the former many routers cannot sustain full bandwidth. Your Firewalla gold plus for example cannot sustain 2.5 gbps on pppoe connections