eGPUs have all but disappeared. 90% of the models available in 2019 are no longer available with no models to replace them. Even bigger companies like razer and coolermaster seemed to silently discontinue them and simply let the product webpages break down. I think power requirements of the last years of GPUs have also made them less practical and people aren’t going to pay 500€ for an enclosure when that is simply approaching the cost of the rest of the PC.

There are even fewer thunderbolt4 but thunderbolt3 has a bit of latency results in slight performance loss, so finding an old model enclosure with thunderbolt3 might be your best chance of getting it. Different storefronts sometimes still have a few in stock you can buy.

Edit: Nowhere did I say “no eGPUs have been made” just that there are signifucantly less options than 5 years ago:

https://egpu.io/best-egpu-buyers-guide/

Look at the vendor pages for most of these models and see if you can buy them from tge vendor or an manufacturer-listed distributer and then try to find newer, actively produced eGPUs by the manufacturers (including the big names). For the vast majority they have stopped making them.

To frame it as an example: If you saw that 30 laptop manufacturers making 100+ models in 5 years went to 3 manufacturers making 5 models, you would say that is a very rapid decline.