I would say, make a shortlist of some criteria which are must have and those that are good to have. Personally, I would advise for
minimum 3 HDMI ports
With the above set of features, you are sure to accommodate the current minimum + be safe for a few years ahead. I would not buy a 4k TV
no matter the appeal. I would also quickly glance at one of these reviews here
There is a thread around here for daily deals, sometimes Mediamarkt and similar stores have daily/weekly specials on TVs. Else, toppreise
is your friend.
Whatever you pick, enjoy and may it serve you well.