issue max value for records inserted all take number 4 i need it 4,5,6

Question

I need to insert data to table #t with incremental by 1

so max id for records on #t is 3 so

if i insert multi rows as 4 rows to table #t then it must take 4,5,6,7

but this not happen all records take 4

so how to solve this issue please

i don't need use identity column so how to increment every row by 1 without using identity column

so how to do that please

create table #t
 (
 id int,
 name nvarchar(20)
 )
 insert into #t(id,name)
 values
 (1,'ahmed'),
 (2,'ali'),
 (3,'ala')
    
 create table #t2
 (
 name nvarchar(20)
 )
 insert into #t2(name)
 select 'islam'
 union
 select 'sayed'
 union
 select 'wahdan'
 union
 select 'warshan'
what i try

 insert into #t(id,name)
 select (select isnull(max(id)+1,0) from #t ),name from #t2

expected result

id    name
1    ahmed
2    ali
3    ala
4    islam
5    sayed
6    wahdan
7    warshan