eSIM

One plan would cover many countries......IF......your plan was an international plan. Check with your current carrier to see what they can offer. Most major carriers offer this type of option at a reasonable cost.

For example, with AT&T, you have coverage just about anywhere in the world for about $10 a day. Personally, I just fold the cost into the cost of travel, like a meal or entertainment.

it is tons easier to have one plan and simply log on automatically in each country, rather than try to set up different plans in different countries on the fly, but you can save some money.....but not time....doing it this way.

It depends upon where you are going. In Europe some companies cover several countries. You basically need an eSIM for each company you plan on using.