Would buying a £570 second hand phone on ebay be a bad idea while on uc and pip?

Following my last post. i found this second hand s25 ultra on ebay from a legit business seller and my s22 plus is lagging, battery life isnt that great anymore and software updates will soon run out next year..

Would it be considered reasonable to buy it since I have £6860 savings (£5992 last ap) because I got paid uc and pip (1400 in total) on the 22nd and 20k backdated PIP already declared and disregarded. Im anxious thinking its a bad idea since my ap is in a week.