Here is the profiler report:

CPU:

4003  66% - command-execute
4003  66%  - call-interactively
3913  65%   - funcall-interactively
3320  55%    - kill-buffer
3318  55%     - org-persist-write-all-buffer
3318  55%      - org-persist-write-all
3318  55%       - if
3318  55%        - let
3318  55%         - while
3318  55%          - let
3318  55%           - if
3318  55%            - progn
3318  55%             - org-persist-write
3318  55%              - if
3318  55%               - save-current-buffer
3318  55%                - let
3097  51%                 - let
3097  51%                  - if
3097  51%                   - if
3095  51%                    - progn
3095  51%                     - let
1799  29%                      - unwind-protect
1799  29%                       - prog1
1798  29%                        - save-current-buffer
 114   1%                         - write-region
 114   1%                          - select-safe-coding-system
  98   1%                           - find-auto-coding
  94   1%                              auto-coding-alist-lookup
   4   0%                              sgml-html-meta-auto-coding-function
  15   0%                           + find-coding-systems-region
1290  21%                      - let
1290  21%                       - unwind-protect
1290  21%                        - prog1
1289  21%                         - save-current-buffer
 182   3%                          - write-region
 182   3%                           - select-safe-coding-system
 155   2%                            - find-auto-coding
 154   2%                               auto-coding-alist-lookup
   1   0%                               sgml-html-meta-auto-coding-function
  26   0%                            + find-coding-systems-region
   6   0%                        if
 220   3%                 + org-persist--get-index
   2   0%     + valign--maybe-clean-advice
 592   9%    + counsel-M-x
   1   0%    + previous-line
  90   1%   + ivy-completing-read
 978  16% - youtube-dl--filter
 978  16%  - youtube-dl--redisplay
 585   9%   - youtube-dl--list-buffer
 585   9%    - youtube-dl-list-mode
 332   5%     - hl-line-mode
 332   5%      - add-hook
 332   5%       + sort
 165   2%     + special-mode
  88   1%     + run-mode-hooks
 393   6%   + youtube-dl-list-redisplay
 954  15% + ...
  40   0% + timer-event-handler
   9   0% + redisplay_internal (C function)
   9   0% + global-font-lock-mode-check-buffers
   5   0% + global-dash-fontify-mode-check-buffers
   3   0% + global-prettify-symbols-mode-check-buffers
   3   0% + yas-global-mode-check-buffers
   3   0% + global-atomic-chrome-edit-mode-check-buffers
   2   0% + global-edit-server-edit-mode-check-buffers
   2   0% + global-flycheck-mode-check-buffers
   2   0% + global-company-mode-check-buffers
   1   0% + org-pretty-tags-global-mode-check-buffers
   1   0% + magit-auto-revert-mode-check-buffers
   1   0% + emojify-update-visible-emojis-background-after-command
   1   0% + global-ligature-mode-check-buffers
   1   0% + global-emojify-mode-check-buffers
   1   0% + global-anzu-mode-check-buffers
   1   0% + mode-local-post-major-mode-change

Memory report:

5,860,697,032  99% - ...
5,860,697,032  99%  - org-persist-write-all
5,860,697,032  99%   - if
5,860,697,032  99%    - let
5,860,697,032  99%     - while
5,860,697,032  99%      - let
5,860,697,032  99%       - if
5,860,697,032  99%        - progn
5,860,697,032  99%         - org-persist-write
5,860,697,032  99%          - if
5,860,697,032  99%           - save-current-buffer
5,860,697,032  99%            - let
5,671,666,312  96%             - let
5,671,666,312  96%              - if
5,671,666,312  96%               - if
5,671,666,312  96%                - progn
5,671,666,312  96%                 - let
4,109,383,193  70%                  - unwind-protect
4,109,383,193  70%                   - prog1
4,109,383,193  70%                    - save-current-buffer
    4,825,178   0%                     - write-region
    4,792,442   0%                      + select-safe-coding-system
       32,736   0%                      + make-lock-file-name
       39,558   0%                     + prin1
1,562,123,885  26%                  + let
       32,736   0%                  + if
       28,290   0%                    generate-new-buffer
  189,030,720   3%             - org-persist--get-index
  189,030,720   3%              - let*
  189,030,720   3%               + let
    5,807,484   0% + command-execute
    1,312,080   0% + redisplay_internal (C function)
       89,824   0% + youtube-dl--filter
        2,198   0% + timer-event-handler
           42   0% + #<compiled -0x2222a52d2f12599>