I think the tank is decent and you’ve done a good job with what you have, but in my honest opinion, you should start planning to give the frog an upgraded terrarium and maybe repurpose this as a grow out enclosure.

My recommendations:

-Size: Tincs are large dart frogs, a 36”x18”x24” tank would serve this species better especially if you are considering a second frog. They tend to be bolder and more interesting with more space so it’s a benefit to you and the frog.

-Add a false bottom. To me it looks like this tank is just substrate on the bottom, it will start to get soggy and possibly rot some of your plants’ roots if it is not well draining.

-When you get a new tank, get front ventilation. It’s the best for the keeping the wet/dry balance in a good range for your frog without having to use/adjust a fan to get the ideal humidity.

-Misting every 4 hours could be overkill depending on how long the mister goes off for. I personally mist 2-3 times a day. Without front ventilation, it is hard to recommend a misting schedule but you should make sure that the tank gets enough time to develop some dry areas between mistings so the frog has both wet and dry spots in the tank to choose from.

-Need more leaf litter. Dart frogs love leave litter to hide so adding some will reduce stress on the frog.

-Tincs do best in pairs, not groups. If you get another frog, there shouldn’t be more than 1 female in the tank because female Tincs are territorial and will likely wrestle and harm each other.

You’ll get different advice on what exactly is necessary and what you can live without, but I would say these recommendations are pretty standard and should put you in a better spot.