[Which device to buy? Choices choices...]

I think my iMac has come to the end of its useful life with me, it's struggling to keep up with my basic photo editing requirements. The main thing I want a new device for is Affinity Photo, other than web browsing and email that's all I use for (tiny bit of web design). I'm not a pro editor, its more a hobby with my DSLR. Want something portable to take away with me this time, not another iMac.

I'm not sure between a MacBook Pro 16" (or a Windows Surface similar spec), or an iPad - any thoughts? How is the iPad AF experience if I went with the top spec Pro, would I miss having a full 'desktop' experience? I take lots of photos of my dog for an instagram account, I must say speed and ease of developing RAW and editing on the go is appealing.

Any quirks between the Mac and Windows versions of AF if I go laptop?

Insights appreciated, thanks.

[Saving as PNG (with TB checked) removes a pixel layer?]

Thanks got your help @Joachim_L - When I export this ungrouped file to PNG I still get this...

[Saving as PNG (with TB checked) removes a pixel layer?]

It still doesn't for me *wail*  - I've also noticed that I can't drag the layers anymore the UI doesn't respond. I can still use the arrange buttons just no drag n drop. Have I hit a bug? Seems a bit weird it would also affect PNG exporting too

[Saving as PNG (with TB checked) removes a pixel layer?]

Thanks @walt.farrell ! Sure, I've got a few versions of it now hopefully you can figure it out from this one... 

Luna_Logo_Draft_v03.afphoto

[Saving as PNG (with TB checked) removes a pixel layer?]

Apologies if this has already been covered, I've searched the forum but couldn't find my issue. I've created a logo in AP using several layers, now I have the overall effect I want I've exported as a jpeg no problem all layers are visable although as expected I have the white square background. The logo is all inside a watercolour painted circle (actually a masked inserted image) so I also want to export as a PNG with transparent background, when I do this I lose the pixel layer that is the watercolour painted circle - it's like AP thinks that layer is part of the document background. So frustrating - I've tried so many different merge downs and rasterise, flattern... no matter what I try as soon as I export in PNG with transparent background I lose that layer *sob*

Hopefully someone will understand what I'm going on about. I don't even know what the issue is to be able to search for it effectively.