You might trying moving the inline CSS from the <span> to the <a> where you'd actually need the "words" to break. Im not sure if the <a> will inherit the properties of a parent <span> for wrapping text in Outlook or not?
As an alternative, you could try just using the text "Click Here" (or something like that) inside the <a> element (as linked text) and then separately below the link include the string to copy/paste, or choose one or the other?
I'd think if the button link didn't work for a user that just adding a string to copy/paste would work better than including a redundant link around the string (which didn't work on the button) in the first place?
You might also consider trying to use the string inside different parent elements like:
<p style="overflow-wrap: break-word; word-wrap: break-word;">
If the button above doesn’t work, paste this link into your browser: <br>
<span style="text-decoration: underline; color: #002855;">https://au01web.zoom.us/w/63916266746?tk=qeHmhm9-PCCdAK0ab3_IQKMDsNpc_Za7As6YOr-H5gw.DQMAAAAO4bTU-hpmYWtlZGR3ZGxpUUtSbS16S2dFamVFRVFHUQAAAAAAAAAAAAAAAAAAAAAAAAAAAAA&pwd=S3JhdC9DbzJSeVFMQ3g1VURSZk9UZz09</span>
</p>
^ no <a> element, just text inside a paragraph with a colored span around the link string
or
<div style="overflow-wrap: break-word; word-wrap: break-word;">
If the button above doesn’t work, paste this link into your browser: <br>
<span style="text-decoration: underline; color: #002855;">https://au01web.zoom.us/w/63916266746?tk=qeHmhm9-PCCdAK0ab3_IQKMDsNpc_Za7As6YOr-H5gw.DQMAAAAO4bTU-hpmYWtlZGR3ZGxpUUtSbS16S2dFamVFRVFHUQAAAAAAAAAAAAAAAAAAAAAAAAAAAAA&pwd=S3JhdC9DbzJSeVFMQ3g1VURSZk9UZz09</span>
</div>
^ same as above, but using a <div> instead of a <p> as the parent
or
<p>If the button above doesn’t work, paste this link into your browser:</p>
<div style="overflow-wrap: break-word; word-wrap: break-word; text-decoration: underline; color: #002855;">
https://au01web.zoom.us/w/63916266746?tk=qeHmhm9-PCCdAK0ab3_IQKMDsNpc_Za7As6YOr-H5gw.DQMAAAAO4bTU-hpmYWtlZGR3ZGxpUUtSbS16S2dFamVFRVFHUQAAAAAAAAAAAAAAAAAAAAAAAAAAAAA&pwd=S3JhdC9DbzJSeVFMQ3g1VURSZk9UZz09
</div>
^ separate a <p> from the link text using different parent elements.
Without testing any of these, I'd guess that the closer you get to having the inline style directly wrap the string, the closer you're chances of success. Likewise, the more nested the elements, the less likely it's behave the way you'd expect in email -- specifically Outlook.
Let me know if any of these solutions worked for you?