Strange. I am using version 2 of the /dev/gpiochip API on my recently updated Pis (mainly because API 2 has broken API 1).
Version 2 of the gpiochip API is present in all the Pis I have recently updated (32 and 64 bit).
For instance my Pi3B+
uname -a
Linux pi3bp 5.10.17-v7+ #1421 SMP Thu May 27 13:59:01 BST 2021 armv7l GNU/Linux
A fragment of /usr/include/linux/gpio.h
#define GPIO_V2_LINES_MAX 64
/*
* The maximum number of configuration attributes associated with a line
* request.
*/
#define GPIO_V2_LINE_NUM_ATTRS_MAX 10
/**
* enum gpio_v2_line_flag - &struct gpio_v2_line_attribute.flags values
* @GPIO_V2_LINE_FLAG_USED: line is not available for request
* @GPIO_V2_LINE_FLAG_ACTIVE_LOW: line active state is physical low
* @GPIO_V2_LINE_FLAG_INPUT: line is an input
* @GPIO_V2_LINE_FLAG_OUTPUT: line is an output
* @GPIO_V2_LINE_FLAG_EDGE_RISING: line detects rising (inactive to active)
* edges
* @GPIO_V2_LINE_FLAG_EDGE_FALLING: line detects falling (active to
* inactive) edges
I suggest you update your Pi, perhaps with:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get autoremove