Hi Joey:

Welcome to the HUBB community.

Unless you plan to travel like Jules Verne (around the world in 80 days), it won't be practical to obtain all the necessary visas in advance of your departure.

This is because visas for many countries have a relatively short window of opportunity for one to use them, either because the visa expires within a short period of time (e.g. 6 months), or because the visa specifies that entry to the country needs to be accomplished prior to a certain date (typically 90 days from date of issue for countries that specify a "use by" date).

You'll need to do a fair amount of research before you go to determine where it is possible (and more importantly, NOT possible) to obtain a visa in a second country for entry into a third country. For example, if you are a UK citizen, you can probably obtain a visa while in Canada (2nd country) for entry into the United States (3rd country). But you might not be able to obtain a visa in Lower Slobbovia for entry into Outer Mongolia.

It is possible that in the case of certain countries that have very complicated processes for issuing visas (Russian Federation comes to mind) that it might be prudent to obtain a visa in your home country even if you know it will expire before you need to use it. I say that because when you apply for a visa the second time (from a country other than your home country), 90% of the necessary paperwork & records will already be on file and the process will be much faster and more trouble-free.

Again, do the research... you have lots of time to do that whilst the pandemic rages on. Also, consider getting a fresh UK passport, "business size" (with 48 pages, rather than the usual 24) before you begin collecting visas or depart on your trip.

Michael