People are going to recommend pushups because of course they are. The problem with pushups is you plateau relatively quickly and need to do a ton of reps to make any progress, which is inherently limiting to strength and muscle growth due to the amount of fatigue you get from doing so many reps. Being really tired means your body has to spend more resources recovering and thus has less for building muscle. This is true for pretty much all body weight exercises unfortunately (caveats notwithstanding). Bands will be equally limiting due to the lack of progressive overload (caveats caveats). You could do progressive overload by doing pushups with stuff on your back, but that’s pretty awkward and uncomfortable and can seriously impact your form.

There are a large number of chest exercises available if you are willing to invest in some actual weights. If you have the room I would recommend finding a cheap barbell and some plates, which you can usually find used on craigslist, and a cheap bench (such as this) and rack (such as this). Obligatory fuck amazon, but those examples highlight how cheap the basic equipment can be. The weights will unfortunately be more expensive, depending on what is available locally, but will unlock a ton of exercises beyond the simple bench press. An adjustable bench will allow for all the press variations, and the barbell can be used for a myriad of exercises that cover the entire body, save the lats which are kind of difficult to train with just a barbell. To answer your specific question here the gold standard will always be the standard bench press.

If you don’t have the room or funds for a barbell and plates, I would still recommend at least getting a cheap bench, since that will provide a comfortable platform for other chest exercises (not to mention a lot of other exercises). Another option would be adjustable dumbbells, but unfortunately all the options available have limitations. The all in one adjustable sets (such as these) will cost more than just getting a cheap barbell and plates, and don’t usually have very much mass, which limits their usefulness. The barbell type (I have these) are a bit annoying to use since they are less compact and still require plates. The mass you can put on them is much higher though, so you could easily get by with just those even for leg exercises, despite them being somewhat unwieldy with large plates. You could also get a dumbbell set like those found in commercial gyms, but those are generally quite expensive, require a lot of space to store, and you can only use a small fraction of the total mass at any given time, making them one of the least efficient options for a home gym setup.

If you decide some kind of dumbbell is the best for you I would recommend any of the variations of the dumbbell press, but the best would probably be the dumbbell fly, which requires much less weight to get good tension in the peck muscles and can provide a very deep stretch (which is currently recognized as good for efficient muscle growth). Needing less weight to get the same stimulus means it’s easier to set up, it’s safer to do without risking dropping the weights, and if you do drop the weights there’s less risk of breaking something (or annoying your neighbors). Depending on where you are in your journey you may not even need dumbbells at first, getting a good workout from books or jugs of water, which would save on cost. You could also do this with the bands, but again progressive overload will be a challenge.

At the end of the day the best exercise is the one you enjoy doing, so take people’s advice as a guide and not as prescriptive. If you find an exercise that you like, that feels good, and makes you feel like you’re making progress, stick with it, and try not to hurt yourself. Injuries suck.