Xrhrft

Context:
I just got hired as a software developer in a team which has freshly transitioned from networking to development. Before me they hired another developer a year ago who has been since then given a senior role, he is the only other developer by background in that team. This senior dev and I have graduated from same college and program as well, and this is also our both first job, only difference being he graduated from college before me being older than me. I am saying this to explain how much of a difference he and I have in professional experience.
Our manager is not technical, therefore he is one of those "I care about how much money did it save the company."

Problem:
Because of him being the only dev in the team for more than a year, no one challenged his opinions and ideas on how processes should work. When I joined the team, I saw a team not using Git/GitHub correctly or straight up not using it, no documentation, pushing code directly to production boxes, no collaboration, manual if some testing. (Things are not that bad, the team is learning and they realized they aren't following the best practices.)

When I joined, as in any other team, I started putting my ideas forward, but I am always met with a condescending response ("Do you even know insert given topic") by this senior dev. The rest of the team & manager just side with senior, when I asked them why, the conversation went somewhat like this:

Me: Why do you think this is okay?

Team & manager: He is senior and he knows more.

Me: Why do you think he knows more?

Team & manager: Dude, he uses Linux as his dev environment, he knows a lot.

(That Linux comment actually happened.)

So, I decided to stop getting myself insulted and just do my own thing until maybe more developers are hired and/or we get a technical manager. However, recently I was told to collaborate with this senior on a project, as usual he denied my ideas...which was okay, I decided to play by his rules(not worth my time) until I recently saw my branches and commits being deleted because he had something else in plan, which was not communicated to anyone.

I am still on probation and don't want to cause a drama but it's getting hard not to.

There was a time when I would have said "Stick it out, give things a chance."

That was then and this is now.

I've been where you are. What the "senior" did is unacceptable. Pulling your commits is marginally justifiable, if he IMMEDIATELY issues his design plan document. Deleting your (presumably private) branches is not.

Get out of there. As soon as possible.

You made the mistake so many make.

You came straight from school to your first job and took it upon you to change how the company works.

Nobody cares if your suggestions are good or not, they just see a still green behind the ears graduate who thinks he knows better than everyone before him.

Of course you'll be met with resistance and looked down upon.

So that was why you're in the situation you're in right now.

Your senior either understood you know more than him and views you as a danger to his position or he thinks you're an immature, know it all hack who can't write correct code.

You have two options:

Confront or submit.

If you confront ask why your work was deleted and escalate to superiors if you can prove it was replaced by inferior code.

Be prepared for backlash up to the point that you want to or are forced to look for a new job.

If you submit, just do your tasks and bite your tongue if you have an idea how to optimize the company.

It's not your place until asked to do so, given a position with that responsibility or have your own company that you can run exactly the way you want it to...