TFX keeps performing decently over time but the temps DO degrade. It's a paste, not magic, and no paste is immune to degradation. Seen it on my RTX 3090 FE. Lost about 5C over 4 months.
The best way to avoid degradation is to use liquid metal (usually stable long term, after losing a couple C after a godly temp reduction on direct die (BGA CPU's, desktop GPU's, while it's stable on top of IHS and under IHS due to increased mounting pressure), or to use phase change products, which are largely immune to any of these effects while not being as effective as overall LM, it's more stable long term.
https://www.aliexpress.com/item/3256803559684957.html?gatewayAdapt=4itemAdapt
https://www.moddiy.com/products/Laird-TPCM-780SP-High-Performance-CPU-Interface-Material-(W{47}mK->-5.5).html
