"smooth" base layer similar to R1

What about a light, breathable wind shirt over your base layer, like the Airshed?  It would add warmth but it could be useful if you want to trap that last layer of heat in when you take off your mid layer jacket.

I would take your jacket to the local North Face store and see what they have. TNF has been making some nice grid fleece items lately.

If you can’t find what you are looking for you might experiment with turning an R1 (or similar) inside out.

You could try an expedition weight wool baselayer.

The finish on my mid weight Patagonia Capilene base layers is “smoother”, slippier than exterior of my R1. You could try the Capilene expedition weight base layer.

I second adding in a smooth and UL windshirt over your winter weight base layer. I use a Montane FeatherLite

Although showing signs of wear now it is quite old, I’ve been using it for at least 6 years

https://www.montane.co.uk/mens-c1/clothing-c25/windproof-c12/featherlite-smock-limited-edition-p676

I have a north face summit series l2 fuseform half zip hoodie, polartec grid fleece on the inside and has a polartec hardface outer fabric, I use it as a midlayer with a baselayer underneath. If you hold it up in the light you can see through it due to the grid pattern, so obviously very breathable, if the wind is an issue throw a wind shirt on top and your golden. I actually found it on sale for $112 rather than paying $200. I like the fit 10x better than the patagonia r1. Hope this helps.

Have you looked at the Nano Air Light?  It has a smooth outer, a bit lighter than the R1 and about as warm.  The shell is very breathable.

Revelate Designs Powerline Hoody sounds like just what you need. It’s replaced my R1. Same long fit. Made in the US by NWAlpine for Revelate. Plus they’re on sale:

https://www.revelatedesigns.com/index.cfm/store.catalog/Merchandise/PowerlineHoodie

I’ll second the North Face Summit series L2 Fuseform. The Polartec Hardface smooth exterior is great for layering and did not snag. As usual NF either fits you right or it doesn’t. For me this piece didn’t quite fit me right in certain spots so I begrudgingly returned. It vented off excess heat in high exertion activities like nothing else, but stayed incredibly warm in little movement as well.

Take a look at the nw Alpine black spider hoodie.

They stopped selling it.. but if you can get your hands on Patagonia nano air light hybrid hoody..  pure perfection from the material,  the hood.. and the thumb holes..

I forgot to mention that Grundens sells a hooded top and bottoms in R1 fabric, Pa’lante sells a hooded top, and there are military surplus pullovers in a ‘grid fleece’ that is effectively R1 with more susceptibility to pilling. The later are a slim base layer fit, and cheap enough that you can make your own R1 vest by snipping the sleeves.

I really like the BRYNJE polypropylene tiny fishnet base layers but they are definitely not smooth. For bitter cold I layer polyester base layers over them.  I use either thin or mid weight polyester over the fishnet and the added warmth is pretty amazing. Plus you then get your smooth layering as well as the warmth and the dry feeling the fishnet provides.