It's much more complex and nuanced than "I support this party so therefore fully trust that they will provide the best representatives".

Open list is better, but any sort of list voting is biased against independents, and smaller movements more generally. As I understand it, Finland uses D'Hondt, which is still "vote for one" and if your party doesn't get enough votes to be elected, it's a wasted vote, and there could then be a vote-splitting effect if there are two similar parties that both fail to get a seat, but could have got one between them.

Plus, the open part is also just FPTP within the parties, which isn't very good.

STV is non-monotonic as you say, but there are other methods - approval-based methods such as Phragmén's method, which is monotonic.

Plus the MMP method I discussed further up the thread, which is more independent-friendly and can be used with approval voting.

I agree that parallel MMP is too unproportional, & additional-member (proportional topping-up) adds a prohibitive amount of complication for a first proposal.

But Slovakia, I've read, already has party-list PR, at-large. I don't know why some want to change that.

Open-List PR lets the voters choose who gets the seats that the party wins.

Yes, there's very heavy anti-party sentiment here.
Speaking for myself, I prefer Closed-List PR. If we trust the party central-commuttee (whom we elect locally) to write the platform, then might we not trust them to build & order the candiidate-list, After all the people in the central committee are the ones who are most involved in the creation & running of the party, & in the creation of the platform, Don't you think they're qualified, or don't you trust them, to choose & order the list...from people they know a lot better than you & I do?

But, due the strong anti-party prejudice, I suggest Open-List for the proposal in this country. ...on the Finnish system. Theirs is the exemplary simple, elegant Open--List system,

STV? It's humgously complicated to explain, & expensive to implement. Finnish Open-List doesn't need any new balloting-equipment or any modification of software,

As soon as the vote-count is reported, the allocations to the parties & to their candidates can be done at any kitchen-table where there's a hand-calculator,

Additionally, STV is nonmonotonic, List-PR isn't, unless you use Largest-Remainder (& so you shouldn't),

In STV, changing your ballot in a candidate's favor can make hir lose a seat,

In STV, adding another seat to the house can cause someone to lose their seat.

Is that really what you want?

I claim that limiting your choices to candidates in your local region infringes on & violates your freedom & rights as a voter.

I am all in favour of allowing voters to vote for candidates from anywhere in principle, but do not favour party lists or overly complex ballots.

If anyone wants local representation, then they can get it in an at-large system. A quota of voters of some region has the power to elect someone local as a PM. They could modify their local ballot with the addition of that local candidate. That would work with Open-List, but it could also be arranged with Closed-List.

I claim that limiting your choices to candidates in your local region infringes on & violates your freedom & rights as a voter.

There's no reason to have districts.

No more gerrymandering.
Optimal proportionaity.

At-large PR.

MMP would lose proportional badly if it's the "Parallel" kind. But not if it's the "additional-member" (proportionality top-up) kind. ...at least usually not. Additional-Member systems aren't perfect in their preservation of proportionality. ...& it's a big complication to what would otherwise be a simple PR system.