Input Lag - What the Heck?

I’ve noticed in recent matches (last week or so) that my game will stop for a few seconds, then load 5-10 seconds of time into a “catch up.” It’s definitely not a performance issue. Specs:

AMD Ryzen 7 5800X - 8 Core @ 3.80 Ghz
32 GB DDR4 ram running at 3000 Mhz
M.2 SSD Samsung 980 Pro with heat sink
AMD Radeon RX 6600 running at 45 C under load from AoE2:DE
500 mbps fiber optic

I’ve noticed sporadic posts about this issue since ca. 2021, and many other people who’ve experienced this problem also had ok specs.

Could this be a networking thing? Like my ISP’s fault? I’ve tried playing through a VPN with no change. Would that make a difference?

I would appreciate any help the community can suggest.