Yes, you can lift weights and boulder on the same day. Start with bouldering and leave weightlifting for later in the day. Allow a few hours between the activities to recover. Warm up before each session and cool down afterward. Listen to your body and adjust the intensity if needed.
Yes you can lift weights and boulder on the same day, you just need to be very cautious and listen to your body otherwise you can get injured very quickly. This is especially true if you are new to either bouldering or weight lifting, your muscles and tendons are still adapting and adding extra load to it all can just increase the risk of injury be quite a bit.
If you do, just allow yourself enough rest in between sessions, or, don't max out on both sessions.
Beginner here but I have been doing that for a few month, I don't know if it's ok or not though. I come from a weight lifting background, so to me it just comes natural to lift weight, it's the climbing part that is new for me, and in order to not be in the gym everyday I have been combining sessions. I haven't found what works best yet though as it's pretty random what I do first, either weight lift and then climb or climb and then weight lift.
I haven't gotten injured yet, but that might be because I have been physically active for years now. I would assume that if it's someone who has not been physically active and that climbing is the among the first and only physical activity they do, that they should be more cautious about weight lifting and climbing in the same day and take it slowly.
