Heartily recommend sous vide.
> You can put the meet in a zip lock bag and suck the air out with a straw
You can stay safer by leaving just he corner not zipped and pushing the rest of the bag slowly underwater, it'll squeeze the air out for you.
The oven has a couple benefits.
Everybody has one. Most ovens can get down to 200-275 degrees and stay fairly consistent in temperature. You can take the internal temperature of the meat while its cooking, instead of waiting a set amount of time. The meat comes out dry, which saves you having to dry it coming out of the bag before you sear.
You don't need hundreds, just ~$100 for an inexpensive sous vide cooker with integrated thermometer & temp regulation [0]
You can put the meet in a zip lock bag and suck the air out with a straw and have it work just fine if you want to avoid the added expense of vacuum bags. When the meat hits the desired temp, remove, unwrap, sear the outside, and voila!
[0] https://www.amazon.com/Anova-Culinary-Precision-Bluetooth-In...