const dbName = "test";
const testDB = db.getSiblingDB(dbName);
const coll = testDB.substr_bytes;

testDB.dropDatabase();
coll.insertOne(\{_id: 1, s: "abc"});

const okResult = coll.aggregate([\{$project: {_id: 0, x: {$substrBytes: ["$s", NumberLong("9223372036854775807"), 1]}}}]).toArray();
print("NumberLong(max) result:");
printjson(okResult);

let overflowErr = null;
try {
coll.aggregate([\{$project: {_id:0, x: {$substrBytes: ["$s", NumberDecimal("9223372036854775808"), 1]}}}]).toArray();
} catch (e) {
overflowErr= \{code:e.code, message:e.message};
}

print("NumberDecimal(max+1) error:");
printjson(overflowErr);

NumberLong(max) result:

[
  {
    x: ''
  }
]

{
  code: 50752,
  message: 'Executor error during aggregate command on namespace: test.substr_bytes :: caused by :: $substrBytes:  starting index must be non-negative (got: -9223372036854775808)'
}

NumberDecimal(max+1) error:

{
  code: 50752,
  message: 'Executor error during aggregate command on namespace: test.substr_bytes :: caused by :: $substrBytes:  starting index must be non-negative (got: -9223372036854775808)'
}