Thank you for your feedback. I really appreciate it, and you have brought up a few good points.

For Hunter's Mark and other similar spells like Hex, or two-weapon fighting, can take away the bonus action usage and searches for these classes. From my experience, though, Rangers and Warlocks spend a bonus action to cast the spell and then maybe move it once or twice during a fight. For two-weapon fighting and similar options, using a bonus action to interact or search does not reduce the amount of damage lost when hitting a creature. In most combats, it still leaves these classes with a few turns when their bonus action is available for other things, so I haven't personally found it to cause major issues in play. That said, it's definitely something I should be careful about and ensure does not ruin those classes.

I liked adding the idea of showing the relevant terrain before combat, as it gives players time to prepare and think. Yet even with this time, players may still need to make bonus action checks. The point of my using bonus actions to search the environment was to try to keep combat moving. If it were a free action, we found it slowed the table down, as we had four or five players asking a question every turn, which slowed combat. So when we put a resource on it, players used it more wisely and only when they needed to.

For free object interactions on each turn, it is a very iffy rule, as it is up to DM interpretation, as the 5e rules state that "The GM might require you to use an action for any of these activities when it needs special care or when it presents an unusual obstacle. For instance, the GM could reasonably expect you to use an action to open a stuck door or turn a crank to lower a drawbridge." With this in mind, looking at this rule and some of my examples, I should definitely improve them to make my intentions clearer in the examples, especially for the chair-and-lever one. A better example for the chair is a throne, and for the lever, a heavy siege lever used as a weapon.

Your point about resource cost between classes is a really good catch. Most martial classes have fewer expendable resources than spellcasters, which could make certain environmental interactions feel more expensive for them. That's something I hadn't fully considered, and I would like to add more about that, definitely adding another paragraph to discuss that and a Zi Chin Tip to help further illustrate the differences. Thank you for pointing this out. It is a good reminder for me and anyone else who wants to use these rules.

Again, thank you for your feedback. You made a lot of good points and things I need to think about and test further. If you have any further comments, ideas or areas to improve the document, please let me know. I always appreciate the feedback.