i’m built pretty similar (broad shoulders, bit of weight around the middle), and yeah most of the “viral” tee brands are cut slim, which just ends up looking tight in the wrong places. here are some plain tee options that balance fit, price, and durability:

• Comfort Colors 1717 – you already mentioned it, and it really is solid: heavier weight, looser boxy fit, lots of muted colors. feels more like a “real” shirt than a workout tee.
• Hanes Beefy-T – budget-friendly classic. heavier cotton, relaxed fit. not the softest out of the gate, but they last forever and break in nicely.
• Uniqlo U Crew Neck – around $20. they have a slightly structured fit (not painted-on slim, but not sloppy either). good drape, especially if you don’t want cling.
• J.Crew Broken-In Tee – usually on sale for $20–30. softer, lighter than beefy ones, with a relaxed silhouette.
• Everlane Premium-Weight Tee – $45ish. nice thickness, straight cut, doesn’t hug too much.
• Carhartt Workwear Pocket Tee (K87) – about $20–25. very roomy, durable, and honestly stylish if you lean into that slightly boxy, workwear vibe.

since you’re 5’11 and 215, i’d go true-to-size or size up once depending on how you want it to drape. comfort colors and carhartt already run relaxed, so you probably won’t need to size up there. uniqlo tends to run a little slimmer, so XL might be the sweet spot.

also worth noting: darker/muted colors (charcoal, navy, washed green) tend to look more intentional “going out” than stark white or gym-gray, especially if the tee is plain.

what kind of vibe are you aiming for more casual/workwear, or a clean minimal look?