if you can’t get your haswell qsv to work (it does here, btw) and need to make a move…

at that budget (100gbp ~ 120eur ~ 125usd), your best play might be the cheapest, lowest wattage video card you can find that works with your software and supports at least the encoding you need (if not also newer formats).

you might find something like an alder lake n-series barebones mini pc or itx/matx board/cpu (might not be a ‘drop in’ swap in your t20) for something at least close what you’re looking to spend. anything else for 100 quid is probably gonna be surplus or used stuff you can find locally.