I’d be more concerned with what happens, or could happen, to roaming with a UK SIM post-Brexit.

will the EU telecoms continue to treat UK providers the same with the Roam Like You’re Home regulations, or will UK SIMs be hit with increases costs for roaming around the EU?

this is why I ended up buying an Orange SIM instead, because I couldn’t find an answer to that question. That said, I’ll also need to look into this one to see if or how well it works in Asia, particularly in Taiwan and South Korea.