Sorry for the lengthy reply in advance, but just wanted to respond to a few comments that I missed earlier.

You're getting a lot of advice, but you're the one who knows best what you want to do with your devices. Treat everything as potentially useful information rather than authority. And go slowly!
-- plragde

Of course. I'm just trying to get as much advice as possible so I can (hopefully) decide on a starter rack that is logical and help me on my journey.

Remember that OS 1.3 means your Digitakt can mix input from your modular, pan it dynamically, and apply its effects (and a similar Digitone update is considered likely). Both the Digitakt and the A&H can deal with Eurorack-level signals, but an output module is convenient.
-- plragde

Oh wow, I didn't know this! That's awesome. Out of curiosity - what would be the best way to do this without an output module? I've also got the A&H ZED60-FX mixer, so any recommendations there would be appreciated!

The A&H mixer has 2 headphone sockets - why not just use 1 of them for now? you can add a headphone output in the future if you find you need it!
-- JimHowell1970

I always thought that was the whole point of output modules in eurorack, but seems like I've been wrong about that. As I've asked @plagde - what's the best way to connect it to my mixer/headphones without an output module?

I like FX Aid XL will make a great addition
-- JimHowell1970

I think I'm definitely going to get one of these. After watching a few videos it looks absolutely amazing!

a disting (mk4 or ex) would be a great addition
-- JimHowell1970

I've been doing a bit more research and can see now why a lot of people recommend the Disting MK4 and uO_c modules for a small rack like this. I'm considering adding a uO_c to the rack for quantizing the Digitalis and experimenting with its other uses, then maybe get a Disting after, as it seems like it's a good option to "test" out other functions to help plan future expansion. Do you think this is a good idea? I thought the Marbles and PNW already could already do quantizing, so am I missing something when everyone says the MD needs a quantizer?

Also would having the Salmple, PNW, uO_c and Disting be too much menu diving? I'm trying to avoid this but from what I've seen it doesn't seem too bad. Ideally I'd prefer 1 knob per function but can live with a little menu diving.

Maths not required. If you want more plucky sounds you have a low pass gate built into plaits. From what I can see he likes using plaits to give chord drones. He is using md to drive the melody in the 0 coast.
-- greenfly

This is good to know, thank you. I'm thinking of getting a uO_c instead of the Maths and possibly a Disting MK4 after (as mentioned above). Assume this could open up a world of possibility and keep me busy in the meantime?

I want to underscore what Lugia said about MD needing a quantizer
-- plragde

Yeah this seems to be the general consensus. But as I've asked above in this response. Doesn't the Marbles and PNW act as a quantizer also? And I'm guessing the uO_c or Disting is the solution to this? Seems like the Ladik Q-040 is hard to come by, so maybe I'd be better off with the former as I could also use it for envelope generation, etc?

3xVCA, if you can get it, is a fine bridge to Veils 2020
-- plragde

Good to know! I can't seem to find one for sale. Would the ALM Tangle Quartet work as another solution? Or are there any other alternatives you could recommend?

Also I realised I didn't include any reference videos to the style of ambient that I'd like to make, so better late than never.

This is pretty much the exact style of ambient I am referring to. So Ideally I am trying to build a system that can do both styles of music like the original videos I posted, along with these ones. Am I on the right track with my current setup? I can't really see / am not familiar with the modules in the first video, so would like to know what recommendations everyone has with this in mind. Could the system Lugia proposed achieve this?

Thanks again to everyone for the super insightful and knowledgeable feedback. I will post a picture of my final starter rack once I've decided on my final shopping list in case anyone is interested. I feel like you all are invested in this journey with me now, ha :)