Merging git submodule inside main repository with LFS objects

I am looking in how can I merge existing submodule to my main repository. Basically currently my repository looks somehing like this

├── example1.java
├── example2.java
├── img
|   └── image.jpg
└── submodule
    ├── sub_example1.java
    ├── sub_example2.java
    └── img
        └── sub_image.jpg

And submodule repository itself looks like this

├── sub_example1.java
├── sub_example2.java
└── img
    └── sub_image.jpg

What I am trying to achieve is add this submodule folder inside may main project.

.gitattributes on both repositories looks the same

*.jpg filter=lfs diff=lfs merge=lfs -text
*.png filter=lfs diff=lfs merge=lfs -text
*.odt filter=lfs diff=lfs merge=lfs -text
*.xls filter=lfs diff=lfs merge=lfs -text
*.xlsx filter=lfs diff=lfs merge=lfs -text
*.xla filter=lfs diff=lfs merge=lfs -text

so images from img folders are stored as LFS objects

I have tried to follow some tutorials, for example this one https://stackoverflow.com/a/72557462/8189102 where I would clone main repo and submodule repo beside each other like so

├── main/
└── submodule/

then I would checkout -b a local branch where I want to make changes

$ git checkout -b submodule-merge
$ git submodule deinit -f -- submodule
Cleared directory 'submodule'
error: could not lock config file .git/modules/submodule/config: No such file or directory
warning: Could not unset core.worktree setting in submodule 'submodule'

$ rm -rf .git/modules/submodule
$ git rm -f submodule
rm 'submodule'

Then on the submodule repository I would

$ cd submodule
$ git filter-repo --to-subdirectory-filter submodule
Parsed 501 commits
New history written in 2.12 seconds; now repacking/cleaning...
Repacking your repo and cleaning out old unneeded objects
Updating files: 100% (39508/39508), done.
HEAD is now at fa01cf43 Merge branch 'JRA-2221' into 'master'
Enumerating objects: 44721, done.
Counting objects: 100% (44721/44721), done.
Delta compression using up to 4 threads
Compressing objects: 100% (27931/27931), done.
Writing objects: 100% (44721/44721), done.
Total 44721 (delta 13961), reused 44721 (delta 13961), pack-reused 0
Completely finished after 7.69 seconds.

$ ls -l
submodule

$ git lfs ls-files
119926153d - submodule/img/sub_image.jpg

And then when trying to do the final merge

$ cd main
$ git remote add submodule ../submodule/
$ git fetch submodule
remote: Enumerating objects: 44702, done.
remote: Counting objects: 100% (44702/44702), done.
remote: Compressing objects: 100% (27928/27928), done.
remote: Total 44702 (delta 13950), reused 44700 (delta 13949), pack-reused 0
Receiving objects: 100% (44702/44702), 19.83 MiB | 14.37 MiB/s, done.
Resolving deltas: 100% (13950/13950), done.
From ../submodule
 * [new branch]            JRA-117 -> submodule/JRA-117
 * [new branch]            JRA-221 -> submodule/JRA-221
 * [new branch]            JRA-333 -> submodule/JRA-333
 * [new tag]               b-211      -> b-211
 * [new tag]               b-333        -> b-333

$ git merge --allow-unrelated-histories --no-commit submodule/master
error: Your local changes to the following files would be overwritten by merge:
  .gitmodules submodule

$ git status
On branch submodule-merge
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
    modified:   .gitmodules
    deleted:    submodule

$ git commit -m "Rremoved submodule"
[submodule-merge 1683ee7b89] Rremoved submodule
 Committer: user
 2 files changed, 4 deletions(-)
 delete mode 160000 submodule

$ git merge --allow-unrelated-histories --no-commit submodule/master
Automatic merge went well; stopped before committing as requested

$ git status also shows now all the new files added under submodule folder. Then I commit all the changes

$ git commit -m "Added submodule"
[submodule-merge 332f599182] Added submodule
 Committer: user

$ git status
On branch submodule-merge
nothing to commit, working tree clean

Next I try to push the changes to new branch and I get the following error regarding LFS object

$ git push origin submodule-merge
Locking support detected on remote "origin". Consider enabling it with:
  $ git config lfs.https://gitlab.example.com/main/main.git/info/lfs.locksverify true
Unable to find source for object 65cbf95fd1c7984cc8aca10ef81901e59e5bd42e05d177d1f7b6c95237a20b49 (try running git lfs fetch --all)
Uploading LFS objects:   0% (0/96), 0 B | 0 B/s, done.
error: failed to push some refs to 'gitlab.example.com:main/main.git'

And I get stuck here with no idea what to do. Also when running $ git lfs ls-files | grep 65cbf95f on both repositories (main and submodule) There are no results, its like this object has reference somewhere but actually it does not exist.

I would be very thankful if someone could help me to solve this. Thank you!