Good old PHP and HTML+vanilla JS

Your laptop has an integrated gpu (intel uhd graphics 620). A pretty weak one but it should be fine if you’re just trying things out.

As for an external gpu, although there is a performance hit using thunderbolt it should work much better than your iGPU. That being said eGPU enclosures are pretty expensive and not worth imo if you just want to play around with graphics. You might be better off buying a newer laptop with a GPU or a desktop PC.

Here’s a video of a laptop similar to yours using an eGPU. https://youtu.be/EcrcF9wwT3E