Proxies themselves shouldn't be doing SVCB/HTTPS RR lookups to get A/AAAA records.
As such, draft-pauly-httpbis-alias-proxy-status only needs to look at CNAME chains.
(A question might be whether any special handling is needed for DNAME? That might be its own issue.)
Per draft-ietf-dnsop-svcb-https-11 section 3.2 clients MUST send the final TargetName to proxies: https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-svcb-https-11#section-3.2
Proxies themselves shouldn't be doing SVCB/HTTPS RR lookups to get A/AAAA records. As such, draft-pauly-httpbis-alias-proxy-status only needs to look at CNAME chains.
(A question might be whether any special handling is needed for DNAME? That might be its own issue.)