SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Offering Costs (Q3) (Details) - USD ($)		3 Months Ended	6 Months Ended	9 Months Ended
Sep. 22, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Sep. 30, 2021
Offering Costs Abstract [Abstract]
Offering Costs	$ 339,752
Offering costs charged to stockholders' equity	313,144
Offering costs expensed to operations	$ 26,608	$ 0	$ 355,812	$ 355,812	$ 0

Amount of decrease in additional paid in capital (APIC) resulting from direct costs associated with issuing stock. Includes, but is not limited to, legal and accounting fees and direct costs associated with stock issues under a shelf registration.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

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