Welcome.
That receiver was always a good basic performer. The biggest issue with those older receiver is that they don't fare all that well with low impedance loads, so you have to pick your speakers carefully.
Your turntable is not the worst in the world by a long shot. You might want to start by upgrading the cartridge. Good older turntable go for a fortune. They have become "investment collector" items. I think for a start the one you have will do fine for now.
The speakers need to be good and efficient.
I would recommend these Heco speakers, which right now are on
sale at an incredible value. They are a three way designed right. They have a midrange driver covering the whole of the speech discrimination band. They were
reviewed and measured here by James Larson. From the measurements and his listening opinions I think they will outperform speakers many times their price. I think they will be a good match for your Sansui.
If you want to upgrade your cartridge I would suggest the
Ortofon Blue.
If you want to upgrade your turntable
something like this would fit the bill. If you really want to splurge then go for an Ortofon Black cartridge.
The biggest limitation will be that Sansui receiver, as speaker designers now assume speakers will be used with a sub. That would not be possible to do elegantly with that Sansui. However those Heco speakers have respectable response to 40 Hz, but the last octave will be significantly down.
Anyhow, this will get you a good start.