Trebleet makes a dedicated TB3 case, and one that is ‘compatible’ but limited to USB 3.2 speeds. If you’ve got their 40Gbps model, then there are a couple of other things to look at.
First is the cable – there are a wide variety, and very few of them actually support the full TB4 spec.
Second is the Mac Studio – if you have the Max, the two front ports are actually USB and will be limited to those speeds. The Ultra has TB4 on the front panel, so if that’s your box I’d look much closer at the enclosure and cable.
Actual TB3/4 cables are a bit spendy, but there’s a lot going on in there.