laravel website freeze after 15-30 refreshes

I have a website which is made in Laravel. it is not too extensive, it uses a mysql database

machine:

microserver (SBC)
CPU: Intel® Celeron® N5105 4c/4t
MEM: LPDDR4 8GB
Storage: 500GB NVMe

System: Ubuntu 22.04.2 LTS
Web: Apache 2.4.52
PHP: 8.1

when I am using the site relatively slowly, the first server response is after about 200-300ms.
but when i refresh the page 20-30 times fast. the page freezes and you have to wait 5 seconds for the first response from the server next time. sometimes the page slows down after 10 and sometimes even after 30 refreshes it is not a constant value. but once this happens, no other user can load the page at that time and they have to wait 5 or more seconds. after about 20-30 seconds, the website works fast again

Example good result:

after 20-30 refreshes:

it doesn't matter if it performs a request via a domain or to a local server via ip. this is server stats during rapid refreshing while website is frozen:

i tried:
changing apache2 to use php-fpm (https://www.digitalocean.com/community/tutorials/how-to-configure-apache-http-with-mpm-event-and-php-fpm-on-ubuntu-18-04)
reinstalled whole ubuntu and configured with nginx

unfortunately the problem still exists I'm wondering if the problem is with the server itself or with the configuration. it seems to me that the server is quite strong for these needs and should easily withstand this load - it's like 20-30 people browsing my site at the same time.

I also set up the smallest possible VM on GCP - this is e2-micro (0.25-2 vCPU 1GB MEM) - installed my website there THE PROBLEM DOESN'T OCCUR :O I can refresh it 50 or 100 times. Can someone tell me why on my server this is working so badly. it's at least 4 times better than the one on gcp

SHOW VARIABLES;

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slave_parallel_workers	4	
slave_pending_jobs_size_max	134217728	
slave_preserve_commit_order	ON	
slave_rows_search_algorithms	INDEX_SCAN,HASH_SCAN	
slave_skip_errors	OFF	
slave_sql_verify_checksum	ON	
slave_transaction_retries	10	
slave_type_conversions		
slow_launch_time	2	
slow_query_log	OFF	
slow_query_log_file	/var/lib/mysql/lattepanda-slow.log	
socket	/var/run/mysqld/mysqld.sock	
sort_buffer_size	262144	
source_verify_checksum	OFF	
sql_auto_is_null	OFF	
sql_big_selects	ON	
sql_buffer_result	OFF	
sql_generate_invisible_primary_key	OFF	
sql_log_bin	ON	
sql_log_off	OFF	
sql_mode	ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_...	
sql_notes	ON	
sql_quote_show_create	ON	
sql_replica_skip_counter	0	
sql_require_primary_key	OFF	
sql_safe_updates	OFF	
sql_select_limit	18446744073709551615	
sql_slave_skip_counter	0	
sql_warnings	OFF	
ssl_ca	ca.pem	
ssl_capath		
ssl_cert	server-cert.pem	
ssl_cipher		
ssl_crl		
ssl_crlpath		
ssl_fips_mode	OFF	
ssl_key	server-key.pem	
ssl_session_cache_mode	ON	
ssl_session_cache_timeout	300	
statement_id	1151955	
stored_program_cache	256	
stored_program_definition_cache	256	
super_read_only	OFF	
sync_binlog	1	
sync_master_info	10000	
sync_relay_log	10000	
sync_relay_log_info	10000	
sync_source_info	10000	
system_time_zone	CEST	
table_definition_cache	2000	
table_encryption_privilege_check	OFF	
table_open_cache	4000	
table_open_cache_instances	16	
tablespace_definition_cache	256	
temptable_max_mmap	1073741824	
temptable_max_ram	1073741824	
temptable_use_mmap	ON	
terminology_use_previous	NONE	
thread_cache_size	9	
thread_handling	one-thread-per-connection	
thread_stack	1048576	
time_zone	SYSTEM	
timestamp	1688073784.830778	
tls_ciphersuites		
tls_version	TLSv1.2,TLSv1.3	
tmp_table_size	16777216	
tmpdir	/tmp	
transaction_alloc_block_size	8192	
transaction_allow_batching	OFF	
transaction_isolation	REPEATABLE-READ	
transaction_prealloc_size	4096	
transaction_read_only	OFF	
transaction_write_set_extraction	XXHASH64	
unique_checks	ON	
updatable_views_with_limit	YES	
use_secondary_engine	ON	
version	8.0.33-0ubuntu0.22.04.2	
version_comment	(Ubuntu)	
version_compile_machine	x86_64	
version_compile_os	Linux	
version_compile_zlib	1.2.13	
wait_timeout	28800	
warning_count	0	
windowing_use_high_precision	ON	
xa_detach_on_prepare	ON	

After a few days of struggling with this problem, I managed to find the cause. My server and domain was configured through the CloudFlare tunnel so as not to expose the IP address in any way on any port, even 80. more information available here:
https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/

it turns out that the traffic that goes through such a tunnel is somehow limited - maybe it's a rate limit. as soon as I reconfigured the dns and indicated the direct IP address of the server in the A record. The server handles thousands of requests without any problem.

If someone in the future would have a problem with this and uses such a tunnel at the same time, it is worth remembering about this limitation