Ubuntu 20.04 LTS is very slow

I just installed Ubuntu 20.04 LTS in a Aspire Z1 – 601
https://www.acer.com/ac/en/IN/conten…l/DQ.SYFSI.002

The computer is very slow and old, I wont upgrade RAM

Please suggest another Flavor very similar to Ubuntu 20.04 LTS but lighter (With Ubuntu Store)

I only want to Browse, Watch YT Videos, post @Twitter and check my email (Gmail and POP3)

Thanks

Camelia