I have exactly the same issue. Even if I’m sat right near the router or access point I get 2 bars and not a full 3!! It’s mad. Data transfer is really really slow.
So I decided to do some side by side tests with my work iPhone 8 about 2 years older however I get about 4 times faster in data rate, same test, same files.
test range by walking away from an AP or router. iPhone 8 solid, great signal maintained, iPhone SE 2020. Drops signal, drops to 4G and will not reconnect with SSID, saying wrong password or unable to connect - move closer. TBH if I moved closer I’d be sat on the antenna.
as a previous iPhone SE owner which was great this iPhone is a major disappointment.
all the reviews suggested that this was an updated reworked iPhone 8. It actually falls very very far from an iPhone 8. It’s much worse.
I have done all the supposedly ‘fixes’ offered by Apple and suggestions on this thread and nothing changes.
There is definitely a software, or even worse, a hardware WiFi component problem. If hardware is the cause then this will be Apple in denial that there actually is a problem as they won’t want to fix or recall.!!!!!!
it is bloody annoying.