I have the SABRENT USB-C to 2.5Gbps adapter as well (also bought late 2024) and can echo this sentiment. I had it connected to a M3 Pro MacBook Pro and could never get anywhere close to 2.5Gbps from it. I never found other complaints at the time either and was starting to blame poor wiring in my walls until I replaced it with Ubiquiti's 5GbE adapter (which I believe uses a Marvell controller) and that has been rock solid for me.