Going by Jn 18:22 of WYC, was Jesus slapped OR buffeted on the face?

First, Wycliffe's translation was from the Latin Vulgate, itself a translation from the Greek. That is, the WYC is a translation of a translation and into middle English, which was then (based on the OP's quotation) further translated into modern English.

Here is very literal translation direct from the Greek (BLB):

Now of His having said these things, one of the officers standing by gave a blow with the palm to Jesus, having said, "Do You answer the high priest this way?"

Notice that the Greek noun ῥάπισμα is correctly rendered as "a blow with the palm", ie, a slap!. The word only occurs in three places in the NT, namely, Mark 14:65, John 18:22, and John 19:3. All are correctly translated as either "slap" or, "blow with the palm of the hand".

The above noun is derived from its cognate verb, ῥαπίζω = to slap with the palm of the hand (Matt 5:39, 26:67).

John Wycliffe knew no Greek and thus he translated from the less reliable Latin. At the time (1370's) his translation, almost unreadable now, was a literal Godsend that caused a great spiritual revival. However, English was changing rapidly at the time and Wycliffe's translation was soon overtaken by versions translated directly from the Greek, most notably, that (initially) of Tyndale (1536), etc.