I never came across a Hanimex projector, neither have ever seen a review on it. In Slovakia they must even be much rarer...
There are two main aspects with slide projectors: optics and comfort in handling
Then comes compatibility with the given trays. With 3000 slides this even becomes a main issue, if they are in trays already.
Mains voltage is another issue on the long term with used projectors.
Nevertheless I would just start with any used projector in neat state that appeals to me. Here they are amongst the cheapest photographic items that can be bought locally. I expect that to be the same in Slovakia, though I do not know the spread of projectors over the last decades.
In use certain features may appear that one would like to change, then one may start looking/asking for an apt model.
Otherwise ask member Henning Serger, he made a list with recommended projectors, and is a slide projection specialist here.