Best esim for Italy and England?

Which country are you visiting first? If it's the UK, the I'd recommend giffgaff, which does esims and physical SIMs that it will post overseas. The catch is that you need to use it in the UK first, prior to using it within the EU.

Speaking generally, getting a SIM (eSIM or physical SIM) from a local carrier will be cheaper than one of the travel eSIM providers.

Depends on what you need. If you only need data and don’t want to have to get 2 sims or a physical SIM card, I have used Airalo with the regional Europe esim package successfully a number of times. Actually I am using it in England right now and will be using it in Italy later in this trip. Just a note, I don’t need to make phone calls typically; and if I do, I use Skype or WhatsApp. And many times, WhatsApp will work for receiving calls as well.

I agree with TexasTravelMom, and have also used Airalo with success. Now I have T-mobile, which has a built-in international calling plan, but if I needed an eSIM, I'd go with Airalo.

Airalo has clearly been used by numerous RSers, and several of us have also used Nomad with success. One thing I especially like about Nomad is that all their data plans allow use of the phone as a hotspot, so you can connect your other devices for internet access when wifi is not available. I'd recommend comparison shopping Nomad and Airalo to see which one has the plan best meeting your needs at the better price.

I'll note here that in my travels to Spain and France, the local wireless providers have been unwilling to sell me a non-contract SIM or eSIM. I was able to buy one in Czechia several years ago, but getting it set up was non-trivial; all the directions for activating it were spoken in Czech!

I hotspot my iPad to my phone occasionally using my Airalo plan, in case that matters. I don’t usually have a need for that, though. Definitely compare prices, gigs of data, and length of time you need it.

I've had good luck using an eSIM that covered both Spain and Italy. When I was there, I used Orange Spain and TIM Italy—they had solid coverage in cities and on main roads, but TIM struggled a bit in rural areas. I’d avoid smaller providers as they sometimes had spotty reception outside major towns.

I also tried an eSIM through the TooSim app for about $10 for 5GB over 30 days. Worked fine for data, especially for maps and messaging apps like WhatsApp. Just make sure you’ve checked the network compatibility and avoid auto-switching between SIMs to keep things simple.