Using new (2019) Microsoft Ergonomic Keyboard - how to map emoji and office keys into something usable?

I bought a „Microsoft Ergonomic” keyboard to replace my used up Microsoft Natural. They moved „Win” key to the left and placed new „Office” and „Emoji” keys on the right instead: By default, those keys seem to be not recognized by xorg (at least on Ubuntu 20.04 I use). I am looking for hints how to map those keys. I heavily used Win-… combinations in my custom keyboard shortcuts, so I press those keys repeatedly). I'd prefer to make the Office key behave as Win used to (Super if I recall), and map Emoji as some new modifier. I tried evtest; it emits some key combinations. Both reports below are from a single keypress. (Office)

Event: time 1604935916.773242, -------------- SYN_REPORT ------------
Event: time 1604935919.037417, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e0
Event: time 1604935919.037417, type 1 (EV_KEY), code 29 (KEY_LEFTCTRL), value 1
Event: time 1604935919.037417, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e1
Event: time 1604935919.037417, type 1 (EV_KEY), code 42 (KEY_LEFTSHIFT), value 1
Event: time 1604935919.037417, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e2
Event: time 1604935919.037417, type 1 (EV_KEY), code 56 (KEY_LEFTALT), value 1
Event: time 1604935919.037417, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e3
Event: time 1604935919.037417, type 1 (EV_KEY), code 125 (KEY_LEFTMETA), value 1

(Emoji)

Event: time 1604935938.159725, -------------- SYN_REPORT ------------
Event: time 1604935942.720256, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e0
Event: time 1604935942.720256, type 1 (EV_KEY), code 29 (KEY_LEFTCTRL), value 1
Event: time 1604935942.720256, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e1
Event: time 1604935942.720256, type 1 (EV_KEY), code 42 (KEY_LEFTSHIFT), value 1
Event: time 1604935942.720256, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e2
Event: time 1604935942.720256, type 1 (EV_KEY), code 56 (KEY_LEFTALT), value 1
Event: time 1604935942.720256, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e3
Event: time 1604935942.720256, type 1 (EV_KEY), code 125 (KEY_LEFTMETA), value 1
Event: time 1604935942.720256, -------------- SYN_REPORT ------------
Event: time 1604935942.728233, type 4 (EV_MSC), code 4 (MSC_SCAN), value 7002c
Event: time 1604935942.728233, type 1 (EV_KEY), code 57 (KEY_SPACE), value 1
Event: time 1604935942.728233, -------------- SYN_REPORT ------------
^X@s^[^@Event: time 1604935942.872415, type 4 (EV_MSC), code 4 (MSC_SCAN), value 7002c
Event: time 1604935942.872415, type 1 (EV_KEY), code 57 (KEY_SPACE), value 0
Event: time 1604935942.872415, -------------- SYN_REPORT ------------
Event: time 1604935942.880280, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e0
Event: time 1604935942.880280, type 1 (EV_KEY), code 29 (KEY_LEFTCTRL), value 0
Event: time 1604935942.880280, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e1
Event: time 1604935942.880280, type 1 (EV_KEY), code 42 (KEY_LEFTSHIFT), value 0
Event: time 1604935942.880280, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e2
Event: time 1604935942.880280, type 1 (EV_KEY), code 56 (KEY_LEFTALT), value 0
Event: time 1604935942.880280, type 4 (EV_MSC), code 4 (MSC_SCAN), value 700e3
Event: time 1604935942.880280, type 1 (EV_KEY), code 125 (KEY_LEFTMETA), value 0
Event: time 1604935942.880280, -------------- SYN_REPORT ------------