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Just starting and I plan on jumping ~300 ft towers in the area, what is the need for vents with this scenario?

To keep your canopy cool in the summertime. Hot air can get trapped in the cells and cause too much lift preventing you from being able to descend.

Edited to add an example:

https://www.youtube.com/watch?v=_DVyRtJyDNE

This guy actually wound up dying. He never descended and starved under canopy. BSBD.

For anything over ~220/230' and non-solid it's not going to make much of a difference. From what I've picked up, vents make the canopy start flying faster and keeps it pressurized in the event of a cliff strike or having to ride the wall down. They are also better for deep brake approaches and having the canopy near stalling

Un-vented canopies take a bit longer to start flying (which gives you a little more time to turn it in the event of an offheading), but do poorly if you smack a cliff/building with them.

I'm sure there are other differences and I'm just glossing over it and hitting the high points. From what I can tell, most people jump vented canopies, but some people still jump unvented and it'd definitely be fine for ~300ft non-solid objects.

The lower you jump, the more you need them.
The larger your wing, the more you want them.

I have seen a lot of freestander antenna jumps
in the 200 to 360 feet range and the size of the
jumper and their wing makes a huge difference.

I disagree. We are talking about a coupla meters on heading low openings. And it may give some slight advantage if you gambled and lost on a low sd/off solid jump.
If you are that close to edge........You need more than vents to save your butt.
tcs

Space - vents obviously don't affect the speed of spanwise expansion, but are you really claiming that vents have little effect on canopy pressurization speed?

Faster pressurization = a flyable/steerable canopy sooner. That's a good thing with few, if any, tradeoffs.

a canopy with poor pressurization is still steerable and flyable. I couldn't tell much difference in the overall speed of the blah blah whatever. I pick my gear based on color.

If I have to be staring at a wall I'd rather have a well-vented & fully-pressurized ____ than a half-inflated Raven.

Or if you suck at maintaining your gear and you have a line/lines break on opening, I'd rather have a vented...
https://www.youtube.com/watch?v=KcLQoO_x52E

Yes, That is exactly what I am claiming. But with one exception. If one has a nose first object strike and is sliding down smooth surfaces then the vents could help. But then one would question object choice.
tcs

The half inflated Raven will give you more reaction time. The fully pressurized wing will be moving forward much earlier--giving you less time to react.

Personally, I prefer vents for solid objects, but for post-strike reinflation. I accept that the trade off is that I am more likely to strike the object in the first place (because I will have less reaction time).

After my 180 on "B" on my ACE, I decided that unvented canopy are really faster on rear risers.
But landing on small area or in bad wind is better on vented canopies.