Out of curiosity should a D&D 5e group use roll20 or foundry? Is doing so of the same level of importance as it is for the pathfinder 2 group?
A bit late to the discussion, you've probably made your decision by now. But if you have good bandwidth and don't have heavy storage requirements, you probably are better off with Roll20. I say this as a Foundry user and fan who has been running a 5e campaign in Foundry for about two years.
Actually, I likely would have went with Fantasy Grounds, but I spend most of my time working in a country where internet access is tightly controlled, and it was simply unable to host games using Fantasy Grounds. I was able to participate as a player in one game using Google Fi and VPN but the performance was terrible. Also, I don't really like players having to have to install software on their machines.
Roll20 has performed very well for me, even with subpar bandwidth, even in countries with tight controls on the Internet. Every VTT has a learning curve, but interface preferences is a matter of taste and I focus more on features and performance. Like Fantasy Grounds, you can get official D&D content on Roll20 saving a lot of prep time, especially if you run WOTC adventures.
The main reason I didn't go with Roll20 is that I'm running a campaign with a massive number of maps and many of the maps are large. Even the top subscriber tiers at the time would make it hard to store everything. Also, I found that large maps, with walls and lighting applies, etc. would cause the system to hang and glitch. It just didn't work for me as DM. But I am atypical in my storage needs.
I host Foundry on The Forge and the The Forges hosting service is exceptional. Its designed so that assets load from servers that are closest located to the user geographically so users in different countries have the most optimal performance in terms of load times. This won't matter if you don't have players spread accross multiple countries. And it doesn't apply if you are self hosting or trying to host a game from your personal computer.
In terms of map prep, applying walls is far easier, in my experience, in Foundry compared to Roll20, Fantasy Ground, and d20pro.
The modules are both game changing and frustrating. Best to start with the base system and slowly add community modules after you are familiar with the base functionality. But it is crazy how cool many of the community mods are. If you like to tinker and push the limits of your VTT, Foundry is the way to go. But it can quickly get out of hand with mods that are no longer actively developed, conflict with other mods, or just too many mods that start affecting performance leading to hours of troubleshooting.
Out of the box, the support for 5e isn't great, compared to Fantasy Grounds or Roll20. Even after two years of tinkering and testing, we generally use DnD Beyond for managing character sheets instead of the Foundry 5e character sheets. Only the SRD is supported in Foundry. There are modules that will import from DnD Beyond, but that means you need to buy content on D&D Beyond. You can't just buy non-SRD 5e content natively in Foundry. Moreover, even with D&D Beyond Importing, we fairly frequently run into glitches that require us to go back to the character sheets in D&D Beyond. I've gotten very close to being able to run most 5e from Foundry, but not to where I can fully trust it. And I don't think simply D&D Beyond importing will ever really get Foundry there. Until Foundry or a third-party mod developer can get licensed 5e content, and develop a proper native game system for 5e, it'll always be a kludge.
If you want your 5e stuff to "just work" in a VTT you are better off with a VTT that licenses 5e content and actively develops and supports functionality to work with 5e.
If, however, you don't care much about automating things and having official content available, and are more interested in really slick and useful map and token tools, I've found Foundry to be the best VTT available. Especially if you like to tinker.