Quickbooks want to switch to accrual method but so many things I do not understand

First thing first cash method is straight forward to me but the net profit will always be wrong, for this reason I want so bad to switch because I need to tell exactly how much I am making per month so I can properly manage my funds for paying bills (personal)

Now this is the issue.

With my cash method I just deduct inventory when i purchase for example

100 shampoo bottles purchased for $2.00 on 2/4/2025 = $-200 dollar

now I sell 50 of those bottles at $3.00 = $150.00

Net profit for this month would be $-50.00 but in reality it was $150.00 and left my with inventory of $100.00. So If I tried to pay my bills I would say shit I lost money so I can't touch my earning. ( dont get it wrong I capture a mental image in my head every month to understand that I actually did make money)

Accrual method --- these are my issue and lack of knowledge ( even after watching videos, I can't seem to see how it would fit in easily )

1) I never captured inventory so I need to go back and estimate my inventory for END OF YEAR 2024 ( so I can then get a good enough estimate for beginning of 2025)

2) On quickbooks the second I open a invoice for example for $1000

- Shampoo 300 * $3.00 = $900

- Shipping $100 (flat rate fee )

Automatically quickbooks will put it that I earned a net profit of $1000

The issue with this is that I did not even ship the products out yet since in my business we send on receipt meaning customer must pay me $1000 before shipping these item out.

Why would I want to say I earned profit right away? How about 1 day before end of year I open an invoice for $10000 ( 9800 products, 200 shipping) this would then increase my net revenue for $10000 meaning if my actual net profit was $2000 for the year now it is $12000, then I would pay taxes on $12,000 mean while the customer won't be able to pay for another 2 months ( or better yet customer decides to fully cancel the order) so what now? Did i just pay extra taxes for no reason?

Secondly notice how I keep adding shipping, all my invoices are like this do I have to manually go into quickbooks and then properly change the income? for example 9800 in products (COGS) and then add the $200 ( shipping income) or something like this?

If you guys plan to help I need an example like the above as this is the only way I will understand, I do not need hard to understand definition straight examples are the best way for me to learn.