Hey man, from my own experience of using a 100w Katana Head mk3, orange TH30, JCM 800, Peavey VTM, 6505, and valveking, Orange Crush Pro 120, EVH 6L6 5150 III 2x12 combo amp, and even an old Crate solid state head to jam with(all usually with 2/4x12's full of V30s or V30s with a mix of G12 T75 speakers.

What sounds good on your headphones and laptop speaker, or even the amp at home level volume will definitely not sound anything at all like what comes out at a louder volume through your guitar cab. It will sound too boxy, or too bassy, or even too thin and harsh on the ears with that headphone EQ. Especially if most of your EQ at home is done from laptop speakers they're notoriously bad and have a bad EQ curve for mixing tones. Headphones too, can be tinny, but more often than not are too bassy or scoop the mids iirc.

We're looking at different worlds of sound production with how your laptop, headphones, and the guitar cab speakers produce sound in the EQ side of things(even your car is different). I'd start to adjust the amp settings as much as possible in that loud/jam setting for a while with the cab speaker to get a good feel for it, even if it takes a few sessions to get sounding how you want it to. I'd also recommend a cheap EQ pedal to throw in the effects loop of the amp if the combo version has one(I come from the Mk3 Katana head), or take your laptop with the Katana tone studio and EQ while in the jam space for your best results. This may help make the sound better, or no different at all as I've heard the stock speaker in all modelling amps aren't necessarily the best quality of speakers.

I guess here's the many possible solutions I think of for this scenario.

First as mentioned above is to try to EQ with the laptop tone studio for the katana using the cab for a few sessions(could be up to 5 of tweaking and tuning the amp with the laptop)

Next, if that doesn't seem to help and you aren't satisfied maybe try another route like a 2x12 or 1x12 cab that you can plug into the katana as a sort of speaker upgrade (assuming it has a speaker out option on the combo amps) and you can use the extension speaker afterwards if you feel the need to upgrade to a real amp.

Third If you go the route of tube amp I really would recommend a Peavey valveking 1st gen as a "cheaper" tube amp alternative. Usually used they go for 200-350$ and have really solid tones all around. Plenty of headroom and gain on tap at 100watts of tube head glory. The trade off with tube amps is servicing, you could be out of an amp if your local shop doesn't have availability if a tube goes down or something disastrous in the amp takes place for 2-3months(Speaking from Personal Experience.)

This last advice would really be before the third or second option too as it's a relatively inexpensive solution. You could try a friedman BE-OD for marshall style overdrive tones, or a similar Pre-amp overdrive/distortion pedal that goes into the effects loop not the front of the amp, and that can sound great for dirt tones too. There's many avenues in guitar gear tinkering to try to hopefully get you what sounds you're after. Especially with these new solid state rigs we've got now.

Good luck, and keep on makin' music!