Suggest some good PSU!!

Ig I have problem with my psu, it's deepcool pf550, it's been fine for like 2yrs, but suddenly it's giving me issues like it takes much time to charge and switch on. Like i need to wait 5-10 mins for it to get charged(idk but it works like that). After that 10mins time it's fine, no issues. I searched up the web and found it's a tier E-F psu. I am really confused what psu to buy now. I don't have much budget and whether 550w enough or I need to buy 660w? Please help me out by suggesting some good PSU