I was recently deployed and now have 175 days left until my ETS. According to regulations, am I supposed to return at 90 or 60 days to clear?

If they are going to let you come back from deployment every Soldier has the right to ACAP which you can do 2 years out if you retire and 120-90 days if you're getting out on ETS I've been out for 5 years now but the things change. My advice to you extend there so that you can get the full extent of the Army services to put you in a better position to find you the best job you can get to provide for you and your family good luck war fighter

I'd be MORE worried about a solider NOT focusing on the Duty at hand and only seeing the ETS date. Short timers disease. Can prove to be fatal. And not only for the member but the buddies beside them. Doesn't matter what job MOS NEC you have. If you're NOT focused its a big issue. So. Why would ANY planning command or SFC put a short timer down range?? I know we had plenty of guys who only counted the days. And didnt get alot done to help the command OR the Mission at hand. So. That's a hazard. Straight up. AND. Plenty of times went past those "dates" to fulfill Mission. So. Its never set in stone. Never ever. Not till you're standing tall with Papers IN hand and literally processing OUT.

supposed to be the end of this year for the rest of my unit

Depends if its a Mission Critical job. Been thru this when I was Med retired. It almost cost my Squadron a HUGE crap ton of problems. They CAN keep you right where they want you if its mission critical unless some paper pusher has a plan I was only QA besides the HEAD QA for Airframes. And ya just can't fly without that. So. Sadly another guy from another squadron had to take my place. Mission ALWAYS comes 1st. Sucked too. I went with Wing Admiral and My Skipper to Board to beg them to stop and let me go strictly as an Inspector. But no joy. They didnt care. Plus Clinton was BIG on the downsizing of forces at the time. So any excuse to kick someone out was put into effect. Worse. It took another 16 months to get me finalized out. So. I could've easily deployed to a non fwd area and stayed in and helped my Squadron function without further injury. I just couldn't run _but could've swam which was 100% allowed_thus couldn't pass PFT so NOT mission capable to JAG. Which was BS. Big time. Inspectors dont NEED to run. They need eyes and brains and knowledge of the NATOPS manuals to check flight controls or any other repair done. Geez.
I have a HATE-On for paper wiennies who push regs a tad too far.