It should be possible.

Consider using your UCX II / this setup to
- integrate high-quality external effects, like the Lexicon PCM
- build a parallel effect loop for the amp which keeps the punch/dynamic of an amp and adding FX 100% wet in parallel

You just need to:

    Connect the "Effect send" (preamp signal) to a hardware input, and
    Connect the "Effect return" (power amp) to a hardware output on the UCX II.

Next, connect your external FX unit to the UCX II.
Note: Some units, like the Lexicon PCM81 or PCM91, are stereo, so you'll need to connect both channels.

Finally, route the preamp signal of your amp:

    Directly to the power amp to preserve the punch and dynamics.
    To the external FX, adding the 100% wet signal to the power amp.

This setup provides excellent results.

Additionally, you can use Direct USB recording for backup, capturing the backing track from your PC along with recordings from the amp's mic or line out, depending on your preference.

If you connect your guitar to an instrument input on the UCX II, you can also record the dry guitar signal for reamping later. This allows you to adjust distortion, reverb, or other effects if needed. Simply route the guitar signal back through the amp using another line output from the UCX II.

I've been using a similar setup for home recording for several years with great success.

If the guitar is connected to the UCX II anyway in such a setup you can also make good use of VSTi.
All you need to do is to switch to another TM FX snapshot.

I have several TM FX snapshots for these use cases
   SNAP1 -  "Monitors" to playback sound from the PC on the Main Monitors (Main Out)
   SNAP2 - "HiFi" same for sending the audio signal to the HiFi (Main Out B)
   SNAP3 - "PCM81 -14" for recording the amps and adding external FX (PCM81) with mixer set to -14
   SNAP4 - "PCM81 -18" same as before but 4 dB less FX intensity
   SNAP5 - "PCM91 -13" same as before but with PCM91 and a little bit more FX intensity for the reverb unit
   SNAP6 - "Reamping" - routing for reamping purposes
   SNAP7 - "PCM4DAW" - routing to use both FX units (PCM81, PCM91) for the DAW for mixing and mastering
   SNAP8 - "SGear3" - enable playing through VSTi. which has a Plexi setup with great sound

Check out these blog articles showing how my setup has evolved over time. You'll find pictures of two combo amps and external FX in a stereo setup, mic’d with 2x2 mics (tube and SM57):
https://www.tonstudio-forum.de/blog/ent … iii-en-de/

This post covers my previous analog setup and the transition to an RME-based system, initially using the more affordable Lexicon MX200 as an external mono effect:
https://www.tonstudio-forum.de/blog/Ent … -DURec-DE/

This is what it looks like in action. Immediately ready for operation because all relevant routing and level settings - including those of the external preamps - are stored in the TM FX Snapshot