Question about index on different tablespace and rebuild it

Hello,

I have a database that use index on different table space (nvme). I read
documentation about table space and understand table space cannot be
treated as an autonomous collection of data files.
My question is: Is this always true ? I mean if I have table .. okay
here is example:

create table t1 ( i integer);
create index t1_i_idx on t1 using btree (i) tablespace nvme;

In this case only the index is on different table space nvme that is not
part of data stored into table, I mean if I drop the index, data stored
in table will still be untouched and not damaged.
So in this case if I lost table space nvme that is stored into different
nvme drive, can I insert new one and rebuild all index files with
reindexdb for example or some other tool like
mysql/mariadb for example myismcheck or something like that, that can
rebuild index files when DB sever is offline ?

Regards,
HS