After trying a few different bibs from Ali, I took a punt on these ones from Liteskin: aliexpress.com/item/1005005419167059.html

I'm 176cm and 55-60kg. I used to buy Castelli in S. I chose sizes based on reviews and the sizing charts.

My experiences so far have been:

Darevie - aliexpress.com/item/1005005057467316.html
Tried these in medium. Not compressive enough for my spindly legs. Then I got a small pair which ride up too high. I also had some issues with curling at the leg openings. I can see why people like them, but they didn't work so well for me. I gave the M to a friend and use the S under shorts or on the trainer.

Spexcel - aliexpress.com/item/1005007174629987.html
Tried these in XS. At first, I liked the fabric and leg length and thought they were great, but the black pad is massive and sits really high up my backside so it didn't support me in an aggressive position. The fabric has also come apart at the seams, but that might be because they're so small and tight. Like others, I've had some other issues with customer service and quality fade (jerseys) with Spexcel, so I won't try them again.

Pimmer PNS copies - the original link is gone now (hah, I wonder why) but they are like these: aliexpress.com/item/1005009523096669.html
I'm not into counterfeits and asked for them to have no logo. They arrived with big PNS and Mechanism logos. Like the Spexcel, the fabrics and cut are great but they have that same black pad and it doesn't work for me. If you told me these were made by the same factory that produces Spexcel I would believe you.

Cheji - aliexpress.com/item/1005006397620173.html
Tried these in M. The red pad and fabrics are great. They are slightly short and loose in the leg but nothing too problematic. They were my favourites until I tried the next one from Cheji...

Cheji - aliexpress.com/item/1005009519244192.html
Tried these in S since the M were slightly loose. I got the one with the Elastic Interface pad and it came with hang tags and a little label on the shorts themselves so they seem to be legit (although Cheji isn't listed on the EI website as a brand that officially uses the pads). I also got them with no logo. These are the best so far and probably my favourite bibs ever. They are nice and compressive, don't ride up, the pad is thin and sits just right. If I had to nitpick I would make the straps and legs slightly longer to fit my lanky body but they are just fine as is. They've just increased the price sadly but I think they're still worth it and I'm looking to buy another one or two in the 11/11 sale.

Now on to the Liteskin...

Liteskin - aliexpress.com/item/1005005419167059.html
Tried these in M, as per the sizing chart. Took a punt on these even though there were no reviews since they claim to have MITI bands and an EI pad. However, that was false advertising and the actual product didn't look much like the listing. The pad seemed fake to me and was very soft, the straps were not like the picture and the fabric wasn't what was advertised. I sent the following images and received a full refund. Avoid!
https://mega.nz/file/v8IVjbYb#LDWxaDK2P64BAuyJq2F-JcYksDbhyxynrpqUYqzkziI
https://mega.nz/file/So4jSZ7Z#bnogsPlxk5VKaHCoj3V8c8jcTQzwYuuiiE1yd8qNsLg
https://mega.nz/file/X95TURrZ#i_WN5swUz_2J3qtasFMaY0wliJbikX0Lcm6ZpsPz73E