If statements and RelativePath conversion for Web

I am trying to convert some PowerBI which works on Desktop but not on Web.  It is trying to pull down a long list 100 items at a time, via API.  Based on whether its the first pass or a subsequent pass, move the cursor along to start downloading next batch.

Code below works but has a dynamic URL

FnGetMorePages =
(url, cursor, iter) as record =>
let
// Fetch "page 1" with 100 results on first pass. Then all other passes, grab subsequent pages.
// This logic deals with data sets less than 100 results nicely without errors, as the API errors with cursor=null
agentUrl =
if iter = 1
then url
else Text.Combine({url,"&cursor=",cursor}),
Source = Json.Document(Web.Contents(agentUrl, [Headers = headers])),
data = try Source[data] otherwise null,
next = try Source[pagination][nextCursor] otherwise null,
res = [Data=data, Next=next]
in
res,

trying to replace the agentUrl with [RelativePath=agentUrl] doesnt work so I tried breaking out the If statement

FnGetMorePages =
(url, cursor, iter) as record =>
query = if iter = 1 then
let
Source = Json.Document(Web.Contents("https://xxxxx.net/web/api/v2.1/agents?limit=100", [Headers = headers])),
data = try Source[data] otherwise null,
next = try Source[pagination][nextCursor] otherwise null,
res = [Data=data, Next=next],
in res
else
let
Source = Json.Document(Web.Contents("https://xxxxx.net/web/api/v2.1/agents?limit=100&cursor="&cursor, [Headers = headers])),
data = try Source[data] otherwise null,
next = try Source[pagination][nextCursor] otherwise null,
res = [Data=data, Next=next]
in res,

But his doesnt work.

Any help would be appreciated