my Mac's battery is not increasing HELP

as I said in the title my Mac is charging and the battery is not increasing, but if I don't charge it the battery will get lower. the battery stays the same as long as I charge it but I can't just charge it 24/7 wouldn't that be cause damage? there's no charge to full button on my battery settings. I tried EVERYTHING from google and YouTube, restart smc, clean charging port, trying other's cable+adapter, tried usbc, battery health is normal. like 3 seconds into charging the logo charging on hold was there and then it change to lightning symbol but still never increase. I have exams the whole week and my battery is at 11%. I'm about to crash out and swore to NEVER buy apple again if this problem can't be solved.