We dropped DirecTV for YouTube TV in March 2020. It happened to be coincidental that we did it right around the start of the COVID shutdowns when all the sports leagues went into hiatus. I used MLB.tv to watch the Nats for a while, but I've stopped doing so for reasons I will explain. It's been two or three years since I stopped, so my comments might no longer be entirely accurate as to how well things do or do not work.
I generally had decent—but not fabulous—results using router-level DNS spoofing through Unlocator. They tell you how to set it up and what you need to do on your particular devices to implement it. For TV purposes, we have two TVs with Amazon Fire Sticks, although we never watched baseball on either of those (guest room and master bedroom). The family room TV, which is the one we use the most, has both a first-generation Amazon Fire Cube and a fairly recent Apple TV, and the basement TV has the same model Apple TV. The Apple TV devices worked much better than the Amazon devices did for the DNS spoofing. Unlocator tells you what to do in the Apple TV settings to make it work, whereas the Amazon devices do not have a comparable option and you wind up having to run the Unlocator VPN app on the device before loading MLB.tv. That, in turn, degrades the device's performance. (Let me hasten to add that there is a new version of the Fire Cube on the market that might perform better due to upgraded electronics.) When I attempted to watch MLB.tv on the Fire Cube, the picture would frequently degrade to the point that it was worse than watching a 480i low-def broadcast.
Even with all that set up, it tended to be somewhat hit-or-miss whether I would succeed in watching a Nats game on any given day. Some days, it would say the game is not available in your area; other days, it would work just fine. I tended to have more success streaming day games on my PC while I was working, but even there I sometimes got error messages. There are various reports that MLB does occasionally try to crack down on VPNs and location-spoofing, so maybe that was part of it.
What ultimately soured me on it was two things. First, some Caps games air on ESPN+. The DNS-spoofing settings you need for MLB.tv conflict with watching ESPN+. So in advance of a Caps game on the latter service, I'd have to log into the Unlocator settings on my PC, change them for the Caps game, and then change them back again afterwards. That became a nuisance. Second, and far more importantly in view of the old adage "happy wife, happy life," the DNS-spoofing settings for MLB.tv flat-out prevented my wife from watching her British and Australian programming through TV apps like Acorn TV and Britbox—and she watches that stuff almost every day. I was having to change the settings back and forth twice a day and it was simply too much of a hassle. So when you combined that with the overall hit-or-miss performance that was causing me to miss a fair number of games anyway, I ultimately said it wasn't worth the money and gave up. The only time I've seen a Nats game on TV in the past couple of years was the rare occasion when Apple TV+ or ESPN carried a game.
One other note: Even if you use DNS-spoofing or a VPN, don't try to watch MLB.tv on a device like an iPhone or iPad unless you are actually outside the Nats' TV territory. Those devices use the GPS to determine your location and MLB.tv can access that information. So even though you can view the game, MLB can tell what you're doing, and there have been reports of MLB revoking subscriptions for users who do this. For the most part their policy appears to be "benign neglect" except for people who use GPS-enabled devices.