Warsaw's airport is not huge, and it's pretty easy and relatively quick to connect there (assuming domestic connections). I think we had a 45-50 LOT-to-LOT intra-Europe connection and made it surprisingly easily, with a little time to spare, no long walks or running. Of course, our flights were on time, and there were no other issues.
The big question to ask (with any tight connection) is: How serious would the consequences be if you miss your connection?
Assuming it's all on one ticket (no way would I try on separate tickets), if you misconnect, they'll put you on the next available flight (if they have seats...how many seats do you need? 2? 8? 2 are more likely to be available than 8...). When would the next available flight be - an hour or two later, or the next day? And what is awaiting you at your destination - a cruise ship departing Venice early the following morning, or a relaxed week there in Venice?
So how bad is the risk, how awful would it be if things go sideways? If it's no big deal, then I'd be willing to give that tight connection a chance (I would be looking for better uses of my time than that 14 hour train ride!). But you need to give a hard, sober look at the "what ifs". Another point worth considering: Between now and "this summer" the flight schedules could easily be adjusted - either way: your 35 minute connection could dwindle to an even more alarming number, or could also expand to a comfortable hour-plus. No way to know.
If you do decide to "go for it" it would be prudent to research your options, so you have in your back pocket all the info you would need to quickly pivot to a Plan B (and maybe a Plan C, or D...) as a game-day decision.
Since this "tight connection" would save you pretty much a whole day (that 14-hour train ride is going to consume a full day), it would be very tempting to me. If all goes well, you could pull it off.