jq question regarding transposing json dataset

So I have an interesting issue. I have a json file that I need to convert in the following format preferably using Linux CLI tools. Is JQ a vehicle for that? if so I can use help with that. If not, I'd love to know the logic with which to do it. My language of choice is PHP but I can convert pseudocode to actual code in php if you provide logic.

JSON FILE

{
"30814": {
    "uid":       "Joe.Jones",
    "date":       "2023-05-02",
    "reg":       "7.13",
    "ot":       "0.00"
},
"30870": {
    "uid":       "Joe.Jones",
    "date":       "2023-05-03",
    "reg":       "7.48",
    "ot":       "0.00"
},
"30906": {
    "uid":       "Hank.Joans",
    "date":       "2023-05-02",
    "reg":       "6.37",
    "ot":       "0.00"
},
"31079": {
    "uid":       "Some.User",
    "date":       "2023-05-01",
    "reg":       "5.82",
    "ot":       "0.00"
},
"31125": {
    "uid":       "Some.User",
    "date":       "2023-05-02",
    "reg":       "7.28",
    "ot":       "0.00"
}

}

EXPECTED OUTPUT

<table border=1>
<tr>
 <td> NA
 <td> 2023-05-01 <td> 2023-05-02 <td> 2023-05-03
<tr>
  <td> Joe.Jones
  <td> -  <td> 7.13/0.00  <td> 7.48/0.00
<tr>
  <td> Hank.Jones
  <td> - <td> 6.37/0.00 <td> -
<tr>
  <td> Some.User
  <td> 5.82/0.00 <td> 7.28/0.00 <td> -

</table>

I have a complete brainfog and don't even know what to try. I tried looking up google but this is a specific enough usecase where google searches are not helping me - or I am not searching for right things. The word transposing datasets keeps coming up in my searches but I don't know how to apply logic to solve this.

Except for the ordering of the data rows, here's an all-jq solution:

jq -r '

def tocell:
  "<td>\(.)</td>";

def torow:
  "<tr>",
  (.[]|tocell),
  "</tr>";

def totable: 
  "<table border=1>",
  (.[] | torow),
  "</table>";

[[.[]] 
 | (map(.date) | unique) as $dates
 | ["NA"] + $dates,  # header row
   (group_by(.uid)
    | .[]
    | .[0].uid as $uid
    | INDEX(.date) as $dict
    | [$uid, $dict[$dates[]].reg]
    | map(. // "-") ) ]
| totable
'

The idea is first to produce one JSON array per row, and then to convert the result to HTML.