Edit: This is not a complete answer because it does not explain why you can't buy the warrant and short the stock to get free money. The current (2020-12-06) price of CIIC is $27, while CIICW is $6.50. There is currently a large gap ($27 - 11.50 - 6.50 = $9 gap) between the intrinsic value of the warrant and its actual price, and this situation has persisted for quite some time already. From my understanding, call options do not sell below intrinsic value (assuming positive interest rates), but why do these call warrants sell below their intrinsic value?
I am only retaining the "answer" below for the benefit of those who wish to continue to investigate further.
If I bought a bunch of warrants and exercised them immediately, wouldn't I still have made $22 per warrant ($33.50-$11.50)? Following this logic, shouldn't the warrants have reached a high of at least $22?
You won't be able to do this because the warrants cannot be exercised immediately. From the first page of CIIG Merger Corp's prospectus (Form 424B4 filing dated 2019-12-13):
The warrants will become exercisable on the later of 30 days after the completion of our initial business combination or 12 months from the closing of this offering [...]
CIIG Merger Corp. must complete an initial business combination (e.g. merger with Arrival) before the warrants can be exercised. You can ignore the 12 months condition, because it has been almost 12 months since the initial offering.
According to CIIG Merger Corp's press release about its merger with Arrival:
Both the board of managers and shareholders of Arrival have unanimously approved the proposed transaction, which is expected to be completed in the first quarter of 2021.
As you can see, it will be some time before the warrants can be exercised (merger date + 30 days). In the meantime, a large number of adverse events could affect the value of the warrant. For example, if CIIC stock crashes or the merger is cancelled, the price of the warrant will fall.
Note that the warrants are going to expire worthless sometime in December 2022 (about a year from now) if CIIG Merger Corp. does not manage to complete any business combinations. This warning is repeated countless times in the prospectus. An example of such a warning from page 32 of the prospectus:
There will be no redemption rights or liquidating distributions with respect to our warrants, which will expire worthless if we fail to complete our business combination within the 24-month time period.
There are probably other factors causing the low warrant price. You should read the documents on EDGAR to find out.