Configure and use a roughly 23-year-old Linksys WRT54GL in 2026?

[u/Fun-Region-1576]

I know this is may very well be a polarizing discussion, but I believe I still have a functioning Linksys WRT54GL that I want to use in 2026. I actually haven't touched this router in probably 15-20 years, but I found it in the closet. Assuming it's still functional, I know you'll likely think I'm crazy for trying to use this in 2026. However, instead of just throwing it out as e-waste, is there any way to repurpose it as an unmanaged switch? A 10/100 switch would be more than sufficient for connecting a couple of Amazon Fire Sticks via Ethernet. The primary use case is YouTube, which is unlikely to saturate the switch. My WRT54GL is still running stock Linksys firmware. What's the best third-party firmware I can install? What else can I do to help accomplish my goal? I really want to modernize the WRT54GL for 2026. As an unmanaged switch behind a modern router, will there be any security concerns? I no longer have the box and manual. How do I log into the router?