Stick with the S20 that is a good phone my mums one actually overheated and shut down the phone I had to put a fan on the phone dont upgrade TobyO said it would burst into flames like the Note 7 well there isnt any cases yet and/or if it has and nobody's reported it it would be a danger/risk for you stick with the S20 on the 20th February I'm taking my S21 back and getting the S20 Ultra for my mum instead so stick with the S20 and nobody got hurt when my mums phone was overheating but dont take the risk
this overheating issue is down to faulty batches I'm guessing, personally mine is perfect. really is a premium device from performance,battery,design,screen etc. as for upgrading from S20 series I couldn't really comment,I will say I have the note 10 and the s21 ultra is definitely better 😍. I do feel bad for the people who have received a faulty device which will leave a bad taste in their mouth.
I've had many phones and never ever got as hot as the s21 ultra and could not hold it as was so hot . it turned off messages all the time saying too hot 🔥 I've had s8 s9 plus and S105G ( still using ). and other makes of phones . they never got hot but the S21 ultra was unbelievable hot it was mad had to take outside in cold to cool down ... in my opinion it was dangerous hot 🔥