...I never understand what it means that the ____ gets the beat... as if that note gets the beat what do the other notes get?
The beat unit gets the beat. So in common time - 4/4 - quarter note gets the beat and there are 4 beats per bar. I think you understand that.
The note values smaller than the beat unit are called subdivisions of the beat.
In terms of what do the beats, beat unit, subdivisions, etc. "get", you want to think in general terms of accent which mostly a matter of loudness. Strong and weak beats are the usual names.
The first note of a bar , beat 1, gets accented beats 2 and beyond will be played softer than beat 1. Meters of 4 beats have a bit of a strong accent on beat 3 which sort of makes 4/4 like 2/4 in terms of general accent levels.

The first note of any beat is usually a little stronger in terms of accent that any subdivision after it. The following graphic shows strongness of accent with dots below the notes. 3 dots is strongest, 2 dots medium, 1 dot weak...

You can see a kind of general concept that when anything is divided the first part gets a stronger accent that the remaining part. That applies with any divisions of divions (bar divided into beats, beats divided into subdivisions.)
Maybe a simpler way to put it is: the default accent is medium, beat 1 one is emphasized strong, beat subdivisions are a little weaker than medium.
This model of metrical accent levels applies to any meter. Just identify the beat unit, beat one, and subdivisions. Those are the elements of any meter. The only differ by the specific count.
Keep in mind is is mostly a theoretical description of the hierarchy of accent within metrical divisions. The emphasis is on theory not performance. The overall effect you want it often just a subtle pulse on each beat. Of course many times a performer uses crescendo/decrescendo, swell the loudness up and down over several beats or measures. At that point the actual loudness levels aren't going to match the theoretical model.
Or like I found maybe that a measure works well in 4/4 but I then switched to 7/4 as I wanted 6 half note beats and 1 ...and then to my untrained self the half note feels the same wither is in 7/4 or 6/4
This part of your question is unclear, but maybe this will help.
Meters like 4/4 or 6/4 can have an accent at the half note level...

...that is easy to see, because the number of beats per bar is even.
But, with 7/4, the number of beats is odd, uneven. It's ambiguous how to group accents. Usually 7 is divided into groups of 3 and 4 (or 5/4 divided into 3 and 2, etc...)

If I understood you correctly, you divided the beats evenly then wondered what to do with the remaining one beat...

I think you can leave the last beat unaccented or accented...

Can you get a similar rhythmic feel in 4/4? Yes, but you have to put the accents in places contrary to the basic metric pulse...

That kind of feel is similar to the feel of an odd time signature. (If it happens briefly in otherwise plain 4/4, or if it happens over another simple 4/4 rhythm, it might be better to just call it syncopation.) If you played that pattern constantly some might say it is actually mixed meter...
