Thorens TD 321 Static/ Crackly Sound

I recently purchased a Thorens TD 321 after unanimous recommendation on a previous post. I am new to vinyl so I'm not sure exactly what the issue is, but the sound seems to be excessively crackly/ noisy. The severity varies record to record, but it's present always.

The turntable is grounded and I am using an Audiolab 6000A amplifier.

I have tried brushing the records with a brush provided to me by the person who sold me the turntable, but the noise remains. It unfortunately makes most records unpleasant to listen to, and even those least affected are not worth listening to compared to a clean digital source.

I'm aware some analog 'noise' can be expected with vinyl, but this certainly seems excessive - especially for a 'high-grade' turntable.

I wonder whether the stylus is the issue, although the seller said it was a new (not brand new but newly purchased relatively) cartridge. Perhaps the stylus was damaged in transport or inadvertently by myself when initially handling the turntable.

I can post some videos when I get a chance if that might help troubleshoot the particular noise issue, but I'm looking for any tips/ experience on how I can identify and resolve this issue.

Many thanks!