Firstly, I think you really have to enjoy the hobby of precious metals otherwise it would be easy to lose interest in continuing to make purchases. I have seen many new stackers / collectors enter the market and invest heavily, only to quickly lose interest when the hype disappears and then selling at a loss. Precious metals will rarely make anyone rich but they can be a fun way to accumulate wealth / store funds over a long period and of course hopefully retain purchasing power.
I would always encourage new stackers to make a few sales to become familiar with the process, as it can sometimes be time consuming and may not suit everyone.
However, it was only through experience and selling many items online over a period of time, that I discovered what worked best for me. I remember watching an old you tube video from 'Cull Silver', who is a long term stacker in the USA and he explained that he only truly learned what silver to buy once he had attempted to sell some silver, and this really stuck with me and it's so true.
I guess if I was starting out again in 2021, I personally would focus mainly on bullion sovereigns and Pre 1920 British scrap silver coins, as they are highly liquid and tend to be a spot price play, and limit my premium purchases to a small amount of collectable pieces.
However, i'm sure many other forum members will have different views and ideas and that's what makes this community great.
Finally, there is a lot more resources available now online and via The Silver forum to help new stackers make educated decisions, compared to the limited information available 5 years ago and if you are unsure about anything, you can always ask question via this forum, prior to making a purchase.
Hope this helps.